staging: rtl8723bs: remove duplicate names for _rtw_read16()

staging: rtl8723bs: remove duplicate names for _rtw_read16()

_rtw_read16() is redefined as rtw_read16() and PlatformEFIORead2Byte().
Because rtw_read16() is the only name used in the driver, remove the
duplicate definitions and rename the function from _rtw_read16() to
rtw_read16()

Signed-off-by: Bryan Brattlof <hello@bryanbrattlof.com>
Link: https://lore.kernel.org/r/11458342572f21d9df58b3969ad1f16fdff157f4.1621361919.git-series.hello@bryanbrattlof.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>