wl1271: remove unused flags

These are unused and as with a previous patch 5ef5da for wl1251
this removes some other unused flags. the IRQ_MASK specifically
conflicts with include/pcmcia/cs.h when using compat-wireless.

Cc: Kalle Valo <kalle.valo@nokia.com>
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>