wlcore: Propagate errors from wl1271_read_hwaddr

Propagate errors from wl1271_read_hwaddr. This function is only used
when reading the FW log (following a recovery), so don't read the FW log
in case of a bus error.

Also rename prefixes of wlcore functions which their prototypes had to
be changed.

Signed-off-by: Ido Yariv <ido@wizery.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>