drm/radeon: make functions alloc_pasid and free_pasid static

The functions alloc_pasid  and free_pasid are local to the
source and do not need to be in global scope, so make them static.

Cleans up sparse warnings:
warning: symbol 'alloc_pasid' was not declared. Should it be static?
warning: symbol 'free_pasid' was not declared. Should it be static?
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon_kfd.c

@@ -352,7 +352,7 @@ static uint32_t get_max_engine_clock_in_mhz(struct kgd_dev *kgd)
  */
 static DEFINE_IDA(pasid_ida);
 
-int alloc_pasid(unsigned int bits)
+static int alloc_pasid(unsigned int bits)
 {
 	int pasid = -EINVAL;
 
@@ -367,7 +367,7 @@ int alloc_pasid(unsigned int bits)
 	return pasid;
 }
 
-void free_pasid(unsigned int pasid)
+static void free_pasid(unsigned int pasid)
 {
 	ida_simple_remove(&pasid_ida, pasid);
 }