msm_serial: add missing iounmap() on error in msm_request_port()

Add the missing iounmap() before return from msm_request_port()
in the error handling case.
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Reviewed-by: NIvan T. Ivanov <iivanov@mm-sol.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/msm_serial.c

@@ -637,7 +637,7 @@ static int msm_request_port(struct uart_port *port)
 		if (!request_mem_region(gsbi_resource->start, size,
 						 "msm_serial")) {
 			ret = -EBUSY;
-			goto fail_release_port;
+			goto fail_release_port_membase;
 		}
 
 		msm_port->gsbi_base = ioremap(gsbi_resource->start, size);
@@ -651,6 +651,8 @@ static int msm_request_port(struct uart_port *port)
 
 fail_release_gsbi:
 	release_mem_region(gsbi_resource->start, size);
+fail_release_port_membase:
+	iounmap(port->membase);
 fail_release_port:
 	release_mem_region(port->mapbase, size);
 	return ret;