Input: matrix_keypad - replace header inclusions by forward declarations

When the data structure is only referred by pointer, compiler may not need
to see the contents of the data type. Thus, we may replace header inclusions
by respective forward declarations.

Signed-off-by: Andy Shevchenko <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Dmitry Torokhov <[e-mail]>

include/linux/input/matrix_keypad.h

···
 #define _MATRIX_KEYPAD_H
 
 #include <linux/types.h>
-#include <linux/input.h>
-#include <linux/of.h>
+
+struct device;
+struct input_dev;
 
 #define MATRIX_MAX_ROWS		32
 #define MATRIX_MAX_COLS		32