drm/amd/display: Fix unused variable warning

Some of the newly added code is hidden inside of #ifdef
blocks, but one variable is unused when debugfs is disabled:

drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:8370:8: error: unused variable 'configure_crc' [-Werror,-Wunused-variable]

Change the #ifdef to an if(IS_ENABLED()) check to fix the warning
and avoid adding more #ifdefs.

Fixes: c920888c ("drm/amd/display: Expose new CRC window property")
Reviewed-by: Wayne Lin <Wayne.Lin@amd.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -8379,8 +8379,7 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
 			acrtc->dm_irq_params.stream = dm_new_crtc_state->stream;
 			manage_dm_interrupts(adev, acrtc, true);
 		}
-#ifdef CONFIG_DEBUG_FS
-		if (new_crtc_state->active &&
+		if (IS_ENABLED(CONFIG_DEBUG_FS) && new_crtc_state->active &&
 			amdgpu_dm_is_valid_crc_source(dm_new_crtc_state->crc_src)) {
 			/**
 			 * Frontend may have changed so reapply the CRC capture
@@ -8401,7 +8400,6 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
 				amdgpu_dm_crtc_configure_crc_source(
 					crtc, dm_new_crtc_state, dm_new_crtc_state->crc_src);
 		}
-#endif
 	}
 
 	for_each_new_crtc_in_state(state, crtc, new_crtc_state, j)

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crc.h

@@ -46,13 +46,13 @@ static inline bool amdgpu_dm_is_valid_crc_source(enum amdgpu_dm_pipe_crc_source
 }
 
 /* amdgpu_dm_crc.c */
-#ifdef CONFIG_DEBUG_FS
 bool amdgpu_dm_crc_window_is_default(struct dm_crtc_state *dm_crtc_state);
 bool amdgpu_dm_crc_window_changed(struct dm_crtc_state *dm_new_crtc_state,
 					struct dm_crtc_state *dm_old_crtc_state);
 int amdgpu_dm_crtc_configure_crc_source(struct drm_crtc *crtc,
 					struct dm_crtc_state *dm_crtc_state,
 					enum amdgpu_dm_pipe_crc_source source);
+#ifdef CONFIG_DEBUG_FS
 int amdgpu_dm_crtc_set_crc_source(struct drm_crtc *crtc, const char *src_name);
 int amdgpu_dm_crtc_verify_crc_source(struct drm_crtc *crtc,
 				     const char *src_name,