mmc: rpmb: update size format for write_counter

According to MMC spec, the write_counter is 4-byte length,
use 'int' instead of 'long' type for the 'long' is not 4-byte
in 64 bit CPU.

Signed-off-by: Jason Zhu <jason.zhu@rock-chips.com>
Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>

drivers/mmc/rpmb.c

@@ -67,7 +67,7 @@ struct s_rpmb {
 	unsigned char mac[RPMB_SZ_MAC];
 	unsigned char data[RPMB_SZ_DATA];
 	unsigned char nonce[RPMB_SZ_NONCE];
-	unsigned long write_counter;
+	unsigned int write_counter;
 	unsigned short address;
 	unsigned short block_count;
 	unsigned short result;