mmc: sdio: bind acpi with sdio function device

ACPI spec 5 defined the _ADR encoding for sdio bus as:
High word - slot number (0 based)
Low word  - function number

This patch adds support for binding sdio function device with acpi node,
and if successful, involve acpi into its power management.

Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index d6f20cc..17d7148 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -361,6 +361,8 @@
 
 	unsigned int		actual_clock;	/* Actual HC clock rate */
 
+	unsigned int		slotno;	/* used for sdio acpi binding */
+
 	unsigned long		private[0] ____cacheline_aligned;
 };