staging: gdm724x: Remove test for host endian

gdm_endian.c: small changes were done to remove testing for host
endianness and in-driver conversion for byte-ordering.
The linux/kernel.h functions are used now.

gdm_endian.h: removal of code no longer needed with changes
in gdm_endian.c.

Signed-off-by: Jaime Arrocha <jarr@kerneldev.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>