MIPS: FW: Fix parsing u-boot environment

When reading u-boot's key=value pairs it should skip the '=' and not
use the next argument.
Signed-off-by: Alban Bedel <albeu@free.fr>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8357/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/fw/lib/cmdline.c

@@ -68,7 +68,7 @@ char *fw_getenv(char *envname)
 					result = fw_envp(index + 1);
 					break;
 				} else if (fw_envp(index)[i] == '=') {
-					result = (fw_envp(index + 1) + i);
+					result = fw_envp(index) + i + 1;
 					break;
 				}
 			}