wl1251: Fix NULL pointer dereference
rx51_defconfig: Disable unused usb gadget drivers
board-rx51-camera: Fix compilation without MEDIA_CAMERA_SUPPORT
RX-51: Update hci_h4p board data
Revert "board-rx51-camera: Fix compilation without MEDIA_CAMERA_SUPPORT"

This reverts commit 25cb872b62d687f0d134302bfac6a154e1b8e327.
board-rx51-camera: Fix compilation without MEDIA_CAMERA_SUPPORT

Fix compilation in !CONFIG_MEDIA_CAMERA_SUPPORT case, and make it such
that it is unlikely to cause merge conflicts later.

Signed-off-by: Pavel Machek <pavel@ucw.cz>