mmc: core: Improve documentation of MMC_CAP_HW_RESET

MMC_CAP_HW_RESET means that the controller is capable of resetting the eMMC
device via RST_n signal, not a reset of the controller. Two drivers got
this wrong, so let's make it more clear.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20200821063533.3771-1-wsa+renesas@sang-engineering.comSigned-off-by: NUlf Hansson <ulf.hansson@linaro.org>

include/linux/mmc/host.h

@@ -163,6 +163,7 @@ struct mmc_host_ops {
 	int	(*select_drive_strength)(struct mmc_card *card,
 					 unsigned int max_dtr, int host_drv,
 					 int card_drv, int *drv_type);
+	/* Reset the eMMC card via RST_n */
 	void	(*hw_reset)(struct mmc_host *host);
 	void	(*card_event)(struct mmc_host *host);
 
@@ -346,7 +347,7 @@ struct mmc_host {
 #define MMC_CAP_CD_WAKE		(1 << 28)	/* Enable card detect wake */
 #define MMC_CAP_CMD_DURING_TFR	(1 << 29)	/* Commands during data transfer */
 #define MMC_CAP_CMD23		(1 << 30)	/* CMD23 supported. */
-#define MMC_CAP_HW_RESET	(1 << 31)	/* Hardware reset */
+#define MMC_CAP_HW_RESET	(1 << 31)	/* Reset the eMMC card via RST_n */
 
 	u32			caps2;		/* More host capabilities */