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/card.h b/include/linux/mmc/card.h
index 6ad4355..b460fc2 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -403,4 +403,4 @@
 extern void mmc_fixup_device(struct mmc_card *card,
 			     const struct mmc_fixup *table);
 
-#endif
+#endif /* LINUX_MMC_CARD_H */