wl1271: Remove busy-word checking

Remove busy-word checking to work around an SPI bug. To reduce the
chance of chipset-busy scenarios, increment the number of fixed busy
words.

Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>