rtlwifi: rtl8192cu: Remove sw.h header

It has one define, which is already defined in include from reg.h.
All functions are declared in their own headers and included in *.c
files belonging to them.
This makes sw.h unnecessary, so we can remove it.

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