mmc: sdhci: convert reset into a library function

Rather than having platform_reset_enter/platform_reset_exit methods,
turn the core of the reset handling into a library function which
platforms can call at the appropriate moment in their (new) reset
method.

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/drivers/mmc/host/sdhci-cns3xxx.c b/drivers/mmc/host/sdhci-cns3xxx.c
index 5e0cc9c..87af66b 100644
--- a/drivers/mmc/host/sdhci-cns3xxx.c
+++ b/drivers/mmc/host/sdhci-cns3xxx.c
@@ -83,6 +83,7 @@
 	.get_max_clock	= sdhci_cns3xxx_get_max_clk,
 	.set_clock	= sdhci_cns3xxx_set_clock,
 	.set_bus_width	= sdhci_set_bus_width,
+	.reset          = sdhci_reset,
 };
 
 static const struct sdhci_pltfm_data sdhci_cns3xxx_pdata = {