mmc: core: Convert the error field in struct mmc_command|data into an int

Everybody expects the error field in the struct mmc_command|data to be
and int but it's actually an unsigned int. Let's convert it into an int
to meet the expectations.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

include/linux/mmc/core.h

@@ -79,7 +79,7 @@ struct mmc_command {
 #define mmc_cmd_type(cmd)	((cmd)->flags & MMC_CMD_MASK)
 
 	unsigned int		retries;	/* max number of retries */
-	unsigned int		error;		/* command error */
+	int			error;		/* command error */
 
 /*
  * Standard errno values are used for errors, but some have specific
@@ -108,7 +108,7 @@ struct mmc_data {
 	unsigned int		timeout_clks;	/* data timeout (in clocks) */
 	unsigned int		blksz;		/* data block size */
 	unsigned int		blocks;		/* number of blocks */
-	unsigned int		error;		/* data error */
+	int			error;		/* data error */
 	unsigned int		flags;
 
 #define MMC_DATA_WRITE	(1 << 8)