MIPS: Alchemy: Fix unchecked kstrtoul return value

enabled __must_check logic triggers a build error for mtx1 and gpr
in the prom init code.  Fix by checking the kstrtoul() return value.
Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
Cc: Linux-MIPS <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/6574/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/alchemy/board-gpr.c

@@ -53,10 +53,8 @@ void __init prom_init(void)
 	prom_init_cmdline();
 
 	memsize_str = prom_getenv("memsize");
-	if (!memsize_str)
+	if (!memsize_str || kstrtoul(memsize_str, 0, &memsize))
 		memsize = 0x04000000;
-	else
-		strict_strtoul(memsize_str, 0, &memsize);
 	add_memory_region(0, memsize, BOOT_MEM_RAM);
 }
 

arch/mips/alchemy/board-mtx1.c

@@ -52,10 +52,8 @@ void __init prom_init(void)
 	prom_init_cmdline();
 
 	memsize_str = prom_getenv("memsize");
-	if (!memsize_str)
+	if (!memsize_str || kstrtoul(memsize_str, 0, &memsize))
 		memsize = 0x04000000;
-	else
-		strict_strtoul(memsize_str, 0, &memsize);
 	add_memory_region(0, memsize, BOOT_MEM_RAM);
 }