MIPS: BCM47XX: use common error codes in nvram reads

Instead of using our own error codes use some common codes.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Patchwork: http://patchwork.linux-mips.org/patch/4739/
Signed-off-by: John Crispin <blogic@openwrt.org>
diff --git a/arch/mips/bcm47xx/nvram.c b/arch/mips/bcm47xx/nvram.c
index 6461367..e19fc26 100644
--- a/arch/mips/bcm47xx/nvram.c
+++ b/arch/mips/bcm47xx/nvram.c
@@ -124,7 +124,7 @@
 	char *var, *value, *end, *eq;
 
 	if (!name)
-		return NVRAM_ERR_INV_PARAM;
+		return -EINVAL;
 
 	if (!nvram_buf[0])
 		early_nvram_init();
@@ -143,6 +143,6 @@
 			return snprintf(val, val_len, "%s", value);
 		}
 	}
-	return NVRAM_ERR_ENVNOTFOUND;
+	return -ENOENT;
 }
 EXPORT_SYMBOL(nvram_getenv);