usb/atm/ueagle-atm: Don't test for NULL ptr before calling release_firmware()

release_firmware() deals gracefullt w/ NULL pointers, no need to check
first.

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