build: fix clang warnings

Change-Id: I3c6a63a18034535f0a8c2c62ba8a708f09d7839b
Signed-off-by: Martin Nowak <dawg@dawgfoto.de>
Reviewed-on: http://openocd.zylin.com/765
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>
Reviewed-by: Freddie Chopin <freddie.chopin@gmail.com>

src/flash/mflash.c

@@ -510,7 +510,7 @@ static int mg_mflash_read_sects(void *buff, uint32_t sect_num, uint32_t sect_cnt
 }
 
 static int mg_mflash_do_write_sects(void *buff, uint32_t sect_num, uint32_t sect_cnt,
-	mg_io_type_cmd cmd)
+	uint8_t cmd)
 {
 	uint32_t i, address;
 	int ret;