drm/msm: Fix undefined "rd_full" link error

rd_full should be defined outside the CONFIG_DEBUG_FS region, in order
to be able to link the msm driver even when CONFIG_DEBUG_FS is disabled.

Fixes: e515af8d4a6f ("drm/msm: devcoredump should dump MSM_SUBMIT_BO_DUMP buffers")
Reported-by: Stephen Rothwell <[e-mail]>
Signed-off-by: Bjorn Andersson <[e-mail]>
Reviewed-by: Rob Clark <[e-mail]>
Signed-off-by: Rob Clark <[e-mail]>

drivers/gpu/drm/msm/msm_rd.c

···
  * or shader programs (if not emitted inline in cmdstream).
  */
 
-#ifdef CONFIG_DEBUG_FS
-
 #include <linux/circ_buf.h>
 #include <linux/debugfs.h>
 #include <linux/kfifo.h>
···
 bool rd_full = false;
 MODULE_PARM_DESC(rd_full, "If true, $debugfs/.../rd will snapshot all buffer contents");
 module_param_named(rd_full, rd_full, bool, 0600);
+
+#ifdef CONFIG_DEBUG_FS
 
 enum rd_sect_type {
 	RD_NONE,