staging: r8188eu: remove HW_VAR_ACM_CTRL from SetHwReg8188EU()

SetHwReg8188EU() is called with HW_VAR_ACM_CTRL only from a function
in rtw_wlan_util.c. Move the functionality into a static function in
rtw_wlan_util.c and remove the HW_VAR_ACM_CTRL case from
SetHwReg8188EU(). This is part of the ongoing effort to get rid of the
unwanted hal layer.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20220329202141.7028-5-straube.linux@gmail.com


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