drm/i915/gemfs: don't mark huge_opt as static

vfs_kernel_mount() modifies the passed in mount options, leaving us with
"huge", instead of "huge=within_size". Normally this shouldn't matter
with the usual module load/unload flow, however with the core_hotunplug
IGT we are hitting the following, when re-probing the memory regions:

i915 0000:00:02.0: [drm] Transparent Hugepage mode 'huge'
tmpfs: Bad value for 'huge'
[drm] Unable to create a private tmpfs mount, hugepage support will be disabled(-22).

References: https://gitlab.freedesktop.org/drm/intel/-/issues/4651Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211126110843.2028582-1-matthew.auld@intel.com

drivers/gpu/drm/i915/gem/i915_gemfs.c

@@ -12,6 +12,7 @@
 
 int i915_gemfs_init(struct drm_i915_private *i915)
 {
+	char huge_opt[] = "huge=within_size"; /* r/w */
 	struct file_system_type *type;
 	struct vfsmount *gemfs;
 	char *opts;
@@ -33,8 +34,6 @@ int i915_gemfs_init(struct drm_i915_private *i915)
 	opts = NULL;
 	if (intel_vtd_active()) {
 		if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
-			static char huge_opt[] = "huge=within_size"; /* r/w */
-
 			opts = huge_opt;
 			drm_info(&i915->drm,
 				 "Transparent Hugepage mode '%s'\n",