drm/i915/guc: Move shared data allocation away from submission path

drm/i915/guc: Move shared data allocation away from submission path

We need shared data for actions (e.g. guc suspend/resume), and we're
using those with GuC submission disabled.
Let's introduce intel_guc_init and move shared data alloc there.

This fixes GPF during module unload with HuC, but without GuC submission:

BUG: unable to handle kernel NULL pointer dereference at 000000005aee7809
IP: intel_guc_suspend+0x34/0x140 [i915]
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP
Modules linked in: i915(O-) netconsole x86_pkg_temp_thermal
intel_powerclamp coretemp crct10dif_pclmul crc32_pclmul ghash_clmulni_intel
mei_me i2c_i801 mei prime_numbers [last unloaded: i915]
CPU: 2 PID: 2794 Comm: rmmod Tainted: G     U  W  O 4.15.0-rc2+ #297
Hardware name: /NUC6i5SYB, BIOS SYSKLi35.86A.0054.2016.0930.1102 09/30/2016
task: 0000000055945c61 task.stack: 00000000264ccb43
RIP: 0010:intel_guc_suspend+0x34/0x140 [i915]
RSP: 0018:ffffc90000483df8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff880829180000 RCX: 0000000000000000
RDX: 0000000000000006 RSI: ffff880844c2c938 RDI: ffff880844c2c000
RBP: ffff880829180000 R08: 00000000a29c58c1 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffffa040ba40
R13: ffffffffa040bab0 R14: ffff88084a195060 R15: 000055df3ef357a0
FS:  00007ff43c043740(0000) GS:ffff88084e200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000000f9 CR3: 000000083f179005 CR4: 00000000003606e0
Call Trace:
 i915_gem_suspend+0x9d/0x130 [i915]
 ? i915_driver_unload+0x68/0x180 [i915]
 i915_driver_unload+0x70/0x180 [i915]
 i915_pci_remove+0x15/0x20 [i915]
 pci_device_remove+0x36/0xb0
 device_release_driver_internal+0x15f/0x220
 driver_detach+0x3a/0x80
 bus_remove_driver+0x58/0xd0
 pci_unregister_driver+0x29/0x90
 SyS_delete_module+0x150/0x1e0
 entry_SYSCALL_64_fastpath+0x23/0x9a
RIP: 0033:0x7ff43b51b5c7
RSP: 002b:00007ffe6825a758 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007ff43b51b5c7
RDX: 000000000000000a RSI: 0000000000000800 RDI: 000055df3ef35808
RBP: 0000000000000000 R08: 00007ffe682596d1 R09: 0000000000000000
R10: 00007ff43b594880 R11: 0000000000000206 R12: 000055df3ef357a0
R13: 00007ffe68259740 R14: 000055df3ef35260 R15: 000055df3ef357a0
Code: 00 00 02 74 03 31 c0 c3 53 48 89 fb 48 83 ec 10 e8 52 0f
f8 ff 48 b8 01 05 00 00 02 00 00 00 48 89 44 24 04 48 8b 83 00 12 00 00 <f6> 80
f9 00 00 00 01 0f 84 a7 00 00 00 f6 80 98 00 00 00 01 0f
RIP: intel_guc_suspend+0x34/0x140 [i915] RSP: ffffc90000483df8
CR2: 00000000000000f9
---[ end trace 23a192a61d937a3e ]---

Fixes: b8e5eb960b28 ("drm/i915/guc: Allocate separate shared data object for GuC communication")
Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20171213221352.7173-1-michal.winiarski@intel.com