MIPS: Loongson: Add return value check for strict_strtoul()

cc1: warnings being treated as errors
arch/mips/loongson/common/env.c: In function 'prom_init_env':
arch/mips/loongson/common/env.c:49: error: ignoring return value of 'strict_strtol', declared with attribute warn_unused_result
arch/mips/loongson/common/env.c:50: error: ignoring return value of 'strict_strtol', declared with attribute warn_unused_result
arch/mips/loongson/common/env.c:51: error: ignoring return value of 'strict_strtol', declared with attribute warn_unused_result
arch/mips/loongson/common/env.c:52: error: ignoring return value of 'strict_strtol', declared with attribute warn_unused_result

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/1762/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/loongson/common/env.c

@@ -29,9 +29,9 @@ unsigned long memsize, highmemsize;
 
 #define parse_even_earlier(res, option, p)				\
 do {									\
+	int ret;							\
 	if (strncmp(option, (char *)p, strlen(option)) == 0)		\
-			strict_strtol((char *)p + strlen(option"="),	\
+		ret = strict_strtol((char *)p + strlen(option"="), 10, &res); \
-					10, &res);			\
 } while (0)
 
 void __init prom_init_env(void)