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/ioctl.h b/include/linux/mmc/ioctl.h
index 5baf298..8fa5bc5 100644
--- a/include/linux/mmc/ioctl.h
+++ b/include/linux/mmc/ioctl.h
@@ -51,4 +51,4 @@
  * block device operations.
  */
 #define MMC_IOC_MAX_BYTES  (512L * 256)
-#endif  /* LINUX_MMC_IOCTL_H */
+#endif /* LINUX_MMC_IOCTL_H */