mmc: sdhci: track whether preset mode is currently enabled in hardware

Track whether preset mode is currently enabled in hardware, and use that
when making decisions elsewhere in the code rather than reading the
register and checking the bit.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-by: Markus Pargmann <mpa@pengutronix.de>
Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <chris@printf.net>
diff --git a/include/linux/mmc/sdhci.h b/include/linux/mmc/sdhci.h
index 7f3efba..08abe99 100644
--- a/include/linux/mmc/sdhci.h
+++ b/include/linux/mmc/sdhci.h
@@ -143,6 +143,7 @@
 
 	bool runtime_suspended;	/* Host is runtime suspended */
 	bool bus_on;		/* Bus power prevents runtime suspend */
+	bool preset_enabled;	/* Preset is enabled */
 
 	struct mmc_request *mrq;	/* Current request */
 	struct mmc_command *cmd;	/* Current command */