drm/amd/amdgpu/amdgpu_gmc: Fix a little naming related doc-rot

Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c:487: warning: expecting prototype for amdgpu_tmz_set(). Prototype was for amdgpu_gmc_tmz_set() instead
 drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c:533: warning: expecting prototype for amdgpu_noretry_set(). Prototype was for amdgpu_gmc_noretry_set() instead

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c

@@ -528,7 +528,7 @@ int amdgpu_gmc_allocate_vm_inv_eng(struct amdgpu_device *adev)
 }
 
 /**
- * amdgpu_tmz_set -- check and set if a device supports TMZ
+ * amdgpu_gmc_tmz_set -- check and set if a device supports TMZ
  * @adev: amdgpu_device pointer
  *
  * Check and set if an the device @adev supports Trusted Memory
@@ -574,7 +574,7 @@ void amdgpu_gmc_tmz_set(struct amdgpu_device *adev)
 }
 
 /**
- * amdgpu_noretry_set -- set per asic noretry defaults
+ * amdgpu_gmc_noretry_set -- set per asic noretry defaults
  * @adev: amdgpu_device pointer
  *
  * Set a per asic default for the no-retry parameter.