staging: rts5139: Remove duplicate include of rts51x.h

The header "rts51x.h" is included unconditionally at the start of the
file and then again once more under "#ifdef SUPPORT_FILE_OP".  Once is
enough, so remove the conditional include and just keep the
unconditional one.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>