iommu/vt-d: Fix build error of pasid_enable_wpe() with !X86

iommu/vt-d: Fix build error of pasid_enable_wpe() with !X86

Commit f68c7f539b6e9 ("iommu/vt-d: Enable write protect for supervisor
SVM") added pasid_enable_wpe() which hit below compile error with !X86.

../drivers/iommu/intel/pasid.c: In function 'pasid_enable_wpe':
../drivers/iommu/intel/pasid.c:554:22: error: implicit declaration of function 'read_cr0' [-Werror=implicit-function-declaration]
  554 |  unsigned long cr0 = read_cr0();
      |                      ^~~~~~~~
In file included from ../include/linux/build_bug.h:5,
                 from ../include/linux/bits.h:22,
                 from ../include/linux/bitops.h:6,
                 from ../drivers/iommu/intel/pasid.c:12:
../drivers/iommu/intel/pasid.c:557:23: error: 'X86_CR0_WP' undeclared (first use in this function)
  557 |  if (unlikely(!(cr0 & X86_CR0_WP))) {
      |                       ^~~~~~~~~~
../include/linux/compiler.h:78:42: note: in definition of macro 'unlikely'
   78 | # define unlikely(x) __builtin_expect(!!(x), 0)
      |                                          ^
../drivers/iommu/intel/pasid.c:557:23: note: each undeclared identifier is reported only once for each function it appears in
  557 |  if (unlikely(!(cr0 & X86_CR0_WP))) {
      |                       ^~~~~~~~~~
../include/linux/compiler.h:78:42: note: in definition of macro 'unlikely'
   78 | # define unlikely(x) __builtin_expect(!!(x), 0)
      |

Add the missing dependency.

Cc: Sanjay Kumar <sanjay.k.kumar@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Fixes: f68c7f539b6e9 ("iommu/vt-d: Enable write protect for supervisor SVM")
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Link: https://lore.kernel.org/r/20210411062312.3057579-1-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>