rtlwifi: rtl8192ce: Make functions static & rm sw.h

rtlwifi: rtl8192ce: Make functions static & rm sw.h

Some of functions which were exposed in sw.h, are only used in sw.c, so
just make them static. The rtl92c_init_var_map function is not defined
anywhere, while declared in sw.h. Two other functions are also declared
in phy.h (which is included in sw.c) and their definitions are in phy.c
Overall sw.h is unnecessary and can be removed.

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