bluetooth/ath3kfw: Propagate return value from ath3k_load_fwfile.

The caller ignores the return value so this is a no-op, but
ath3k_init_ar3012 returns the return values of its internal functions,
so this is more consistent.

Fix some misleading indentation while here.

Reported by: GCC -Wunused-but-set-variable (1)