rtlwifi: rtl8192se: Remove sw.h header

It has one define, which is already defined in include from reg.h.
All the declared functions are not implemented anywhere, sw.c has
ones with similar names which are already static.

Signed-off-by: Amadeusz Sławiński <amade@asmblr.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>