mmc: tmio: document CTL_STATUS handling

Now that reading CTL_STATUS is consistent, we can remove CTL_STATUS2 and
document how this is handled internally.
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/tmio_mmc.h

@@ -30,8 +30,9 @@
 #define CTL_STOP_INTERNAL_ACTION 0x08
 #define CTL_XFER_BLK_COUNT 0xa
 #define CTL_RESPONSE 0x0c
+/* driver merges STATUS and following STATUS2 */
 #define CTL_STATUS 0x1c
-#define CTL_STATUS2 0x1e
+/* driver merges IRQ_MASK and following IRQ_MASK2 */
 #define CTL_IRQ_MASK 0x20
 #define CTL_SD_CARD_CLK_CTL 0x24
 #define CTL_SD_XFER_LEN 0x26