usb: composite: Move bitmap related operations to ./include/linux/bitmap.h

The BITMAP related operations can now be moved to ./include/linux/bitmap.h
file to mimic the Linux kernel directory tree.

This change also allows to remove the lin_gadget_compat.h header file
(which is a legacy code only for composite U-boot layer).
It was also possible to remove #includes from several USB gadget drivers.

Signed-off-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Stefan Agner <stefan.agner@toradex.com>
diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
index a3101af..45c7b58 100644
--- a/drivers/usb/gadget/f_mass_storage.c
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -256,7 +256,7 @@
 #include <linux/usb/gadget.h>
 #include <linux/usb/gadget.h>
 #include <linux/usb/composite.h>
-#include <usb/lin_gadget_compat.h>
+#include <linux/bitmap.h>
 #include <g_dnl.h>
 
 /*------------------------------------------------------------------------*/