mmc: core: First step in cleaning up public mmc header files

This is the first step in cleaning up the public mmc header files. In this
change we makes sure each header file builds standalone, as that helps to
resolve dependencies.

While changing this, it also seems reasonable to stop including other
headers from inside a header itself which it don't depend upon.
Additionally, in some cases such dependencies are better resolved by
forward declaring the needed struct.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>

include/linux/mmc/core.h

@@ -8,10 +8,9 @@
 #ifndef LINUX_MMC_CORE_H
 #define LINUX_MMC_CORE_H
 
-#include <linux/interrupt.h>
 #include <linux/completion.h>
+#include <linux/types.h>
 
-struct request;
 struct mmc_data;
 struct mmc_request;