drm/etnaviv: use drm_debug_enabled() to check for debug categories

Allow better abstraction of the drm_debug global variable in the
future. No functional changes.

Cc: Lucas Stach <[e-mail]>
Cc: Russell King <[e-mail]>
Cc: Christian Gmeiner <[e-mail]>
Cc: [e-mail]
Acked-by: Lucas Stach <[e-mail]>
Signed-off-by: Jani Nikula <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/f20[e-mail]

drivers/gpu/drm/etnaviv/etnaviv_buffer.c

···
 
 	lockdep_assert_held(&gpu->lock);
 
-	if (drm_debug & DRM_UT_DRIVER)
+	if (drm_debug_enabled(DRM_UT_DRIVER))
 		etnaviv_buffer_dump(gpu, buffer, 0, 0x50);
 
 	link_target = etnaviv_cmdbuf_get_va(cmdbuf);
···
 	CMD_LINK(buffer, 2, etnaviv_cmdbuf_get_va(buffer) +
 			    buffer->user_size - 4);
 
-	if (drm_debug & DRM_UT_DRIVER)
+	if (drm_debug_enabled(DRM_UT_DRIVER))
 		pr_info("stream link to 0x%08x @ 0x%08x %p\n",
 			return_target, etnaviv_cmdbuf_get_va(cmdbuf),
 			cmdbuf->vaddr);
 
-	if (drm_debug & DRM_UT_DRIVER) {
+	if (drm_debug_enabled(DRM_UT_DRIVER)) {
 		print_hex_dump(KERN_INFO, "cmd ", DUMP_PREFIX_OFFSET, 16, 4,
 			       cmdbuf->vaddr, cmdbuf->size, 0);
 
···
 				    VIV_FE_LINK_HEADER_PREFETCH(link_dwords),
 				    link_target);
 
-	if (drm_debug & DRM_UT_DRIVER)
+	if (drm_debug_enabled(DRM_UT_DRIVER))
 		etnaviv_buffer_dump(gpu, buffer, 0, 0x50);
 }