rt2x00: Fix antenna initialization

Legacy driver indicates that BBP1_TX_ANTENNA must be set
to 0 for TXPATH values of 1 and 3. So the previous statement
that nothing should be done for TXPATH = 3, is false.

Furthermore, remove the false BBP3_RX_ANTENNA initialization
when TXPATH is 1 for PCI and SOC devices. This field will always
be overridden in the next switch statement, making this initialization
bogus. History of this line indicates it was there from the beginning,
and was once caught as typo. Instead of replacing the line with the
correct line, the correct line was added...

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Acked-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>