use proper type for RPMB blocks_cnt

The JEDEC standard is confusing. The number of max blocks for reading
RPMB is determined by CMD23 which can hold an unsigned int and not only
u16. It is true that the current maximum is 64K of blocks, yet this may
be extended in the future. Let's not apply a limit here which should be
checked by the card.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Chris Ball <chris@printf.net>

mmc_cmds.c

@@ -2070,7 +2070,12 @@ int do_rpmb_read_counter(int nargs, char **argv)
 int do_rpmb_read_block(int nargs, char **argv)
 {
 	int i, ret, dev_fd, data_fd, key_fd = -1;
-	uint16_t addr, blocks_cnt;
+	uint16_t addr;
+	/*
+	 * for reading RPMB, number of blocks is set by CMD23 only, the packet
+	 * frame field for that is set to 0. So, the type is not u16 but uint!
+	 */
+	unsigned int blocks_cnt;
 	unsigned char key[32];
 	struct rpmb_frame frame_in = {
 		.req_resp    = htobe16(MMC_RPMB_READ),