wl1271: Change wl12xx Files Names

All files name prefix removed due to the fact that wl12xx driver supports
wl1271 and wl1273.
Also the definition in Kconfig and header files changed respectively.

Signed-off-by: Shahar Levi <shahar_levi@ti.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>