staging: rtl8192e: r8192e_phy: Make functions static

Make as many functions as possible static in r8192E_phy.c.

The following functions were affected:
- rtl8192_phyConfigBB
- rtl8192_SwChnl_WorkItem
- rtl8192_SetBWModeWorkItem

Signed-off-by: Mateusz Kulikowski <mateusz.kulikowski@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>