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/sd.h b/include/linux/mmc/sd.h
index 7d35d52..1ebcf9b 100644
--- a/include/linux/mmc/sd.h
+++ b/include/linux/mmc/sd.h
@@ -9,8 +9,8 @@
  * your option) any later version.
  */
 
-#ifndef MMC_SD_H
-#define MMC_SD_H
+#ifndef LINUX_MMC_SD_H
+#define LINUX_MMC_SD_H
 
 /* SD commands                           type  argument     response */
   /* class 0 */
@@ -91,5 +91,4 @@
 #define SD_SWITCH_ACCESS_DEF	0
 #define SD_SWITCH_ACCESS_HS	1
 
-#endif
-
+#endif /* LINUX_MMC_SD_H */