mmc: Standardize header file inclusion checks.

Standardize the checks for multiple MMC header file inclusion,
including adding comments to terminating #endif's, and fixing
one incorrect comment.

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/include/linux/mmc/pm.h b/include/linux/mmc/pm.h
index d37aac4..4a13920 100644
--- a/include/linux/mmc/pm.h
+++ b/include/linux/mmc/pm.h
@@ -27,4 +27,4 @@
 #define MMC_PM_KEEP_POWER	(1 << 0)	/* preserve card power during suspend */
 #define MMC_PM_WAKE_SDIO_IRQ	(1 << 1)	/* wake up host system on SDIO IRQ assertion */
 
-#endif
+#endif /* LINUX_MMC_PM_H */