wl12xx/wlcore: increase FW filename version

We have some API changes and new features in the new firmwares that
are not compatible with older drivers.  Increase the version of the FW
filenames for wl12xx to 5.

Additionally, remove the duplicate definitions from wlcore_i.h and
remove the MODULE_FIRMWARE macro calls from the SDIO and SPI modules,
since they're irrelevant there.

Signed-off-by: Luciano Coelho <coelho@ti.com>