staging: rtl8723bs: remove duplicate names for _rtw_write16()

_rtw_write16() is redefined as rtw_write16() and
PlatformEFIOWrite2Byte(). Because rtw_write16() is the only name used in
the driver, remove the duplicate definitions and rename the function
from _rtw_write16() to rtw_write16()

Signed-off-by: Bryan Brattlof <hello@bryanbrattlof.com>
Link: https://lore.kernel.org/r/7d53fb295f67f01c72640045afb88150391bce35.1621361919.git-series.hello@bryanbrattlof.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>