staging: rtlwifi: make various structures static

The structures created from macros RTL_DEBUG_IMPL_MAC_SERIES,
RTL_DEBUG_IMPL_BB_SERIES, RTL_DEBUG_IMPL_RF_SERIES and
RTL_DEBUG_IMPL_CAM_SERIES are all local to the source and do
not need to be in global scope, so make them static.

Cleans up 37 sparse warnings of the form:
symbol 'rtl_debug_priv_mac_0' was not declared. Should it be static?

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>