memory: brcmstb_dpfe: Constify the contents of string

The string itself can be made const for safety.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Markus Mayer <mmayer@broadcom.com>

drivers/memory/brcmstb_dpfe.c

@@ -188,7 +188,7 @@ struct brcmstb_dpfe_priv {
 	struct mutex lock;
 };
 
-static const char *error_text[] = {
+static const char * const error_text[] = {
 	"Success", "Header code incorrect", "Unknown command or argument",
 	"Incorrect checksum", "Malformed command", "Timed out",
 };