staging: vt6656: MACvSetKeyEntry change u32 pdwKey to u8 pointer

Change pdwKey u32 pointer to key u8 pointer.

Callers are already u8 remove u32 pointer cast.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>