gfx: build in sgx.o and make sure sgx.o is load after gfx.o

gfx: build in sgx.o and make sure sgx.o is load after gfx.o

Make sure sgx component is initialized after gfx component, otherwise there
will be a BUG:

[    1.320399] BUG: unable to handle kernel NULL pointer dereference at 00000294
[    1.327797] IP: [<c17ecea9>] SYSPVRFillCallback+0x9/0xd0
[    1.333315] *pdpt = 0000000000000000
[    1.335913] sep_sec_driver 0000:00:01.5: Chaabi status from SCU 11112222
[    1.343804] *pde = 20676e696c6c0a0d
[    1.347570] Oops: 0000 [#1] PREEMPT SMP
[    1.351667] Modules linked in:
[    1.354809]
[    1.356444] Pid: 1, comm: swapper/0 Not tainted 3.4.34-00004-g37403a5-dirty #27 Intel Corporation CloverTraill
[    1.367590] EIP: 0060:[<c17ecea9>] EFLAGS: 00010296 CPU: 3
[    1.373221] EIP is at SYSPVRFillCallback+0x9/0xd0
[    1.377970] EAX: 00000000 EBX: 00000006 ECX: 00001211 EDX: 00000000
[    1.384379] ESI: 00000179 EDI: c1e690bc EBP: f2c83f60 ESP: f2c83f5c
[    1.390691]  DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
[    1.396133] CR0: 8005003b CR2: 00000294 CR3: 01e81000 CR4: 000007f0
[    1.402541] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[    1.408849] DR6: ffff0ff0 DR7: 00000400
[    1.412729] Process swapper/0 (pid: 1, ti=f2c82000 task=f2c88000 task.ti=f2c82000)
[    1.420439] Stack:
[    1.422488]  00000006 f2c83f70 c1e13f71 c1c85966 00000006 f2c83fa0 c1201034 00000000
[    1.430746]  c1c1dde4 00060001 c1d4b230 f360a58d c1e13f56 00000000 00000006 00000179
[    1.439003]  c1e690bc f2c83fc4 c1de97f8 00000179 00000006 00000006 c1de92bf c1e689f4
[    1.447143] Call Trace:
[    1.449749]  [<c1e13f71>] PVRSRVDrmInit+0x1b/0x5c
[    1.454512]  [<c1201034>] do_one_initcall+0x34/0x170
[    1.459536]  [<c1e13f56>] ? lowmem_init+0x11/0x11
[    1.464398]  [<c1de97f8>] do_basic_setup+0x8a/0xa3
[    1.469249]  [<c1de92bf>] ? do_early_param+0x74/0x74
[    1.474371]  [<c1de98b0>] kernel_init+0x9f/0x123
[    1.479049]  [<c1de9811>] ? do_basic_setup+0xa3/0xa3
[    1.484172]  [<c19fce3a>] kernel_thread_helper+0x6/0x10
[    1.489444] Code: 26 00 55 89 e5 3e 8d 74 26 00 e8 d3 d1 00 00 5d 83 f8 01 19 c0 f7 d0 83 e0 ea c3 8d b4 26 0
[    1.5041[    1.509336] ---[ end trace e5fdc0f6bb87e119 ]---

Signed-off-by: Yin Kangkai <kangkai.yin@intel.com>