MIPS: Fix read buffer overflow

Signed-off-by: NRoel Kluin <roel.kluin@gmail.com>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/ar7/prom.c

@@ -144,7 +144,7 @@ static char * __init lookup_psp_var_map(u8 num)
 {
 	int i;
 
-	for (i = 0; i < sizeof(psp_var_map); i++)
+	for (i = 0; i < ARRAY_SIZE(psp_var_map); i++)
 		if (psp_var_map[i].num == num)
 			return psp_var_map[i].value;