remoteproc: pru: Replace DEFINE_SIMPLE_ATTRIBUTE with DEFINE_DEBUGFS_ATTRIBUTE

Fix the following coccicheck warning:
./drivers/remoteproc/pru_rproc.c:247:0-23: WARNING:
pru_rproc_debug_ss_fops should be defined with DEFINE_DEBUGFS_ATTRIBUTE
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Link: https://lore.kernel.org/r/1614154829-42461-1-git-send-email-yang.lee@linux.alibaba.comSigned-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/remoteproc/pru_rproc.c

@@ -244,7 +244,7 @@ static int pru_rproc_debug_ss_get(void *data, u64 *val)
 
 	return 0;
 }
-DEFINE_SIMPLE_ATTRIBUTE(pru_rproc_debug_ss_fops, pru_rproc_debug_ss_get,
+DEFINE_DEBUGFS_ATTRIBUTE(pru_rproc_debug_ss_fops, pru_rproc_debug_ss_get,
 			 pru_rproc_debug_ss_set, "%llu\n");
 
 /*