staging: r8188eu: make odm_RSSIMonitorCheck() static

Function odm_RSSIMonitorCheck() is only used in odm.c.
Make it static.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20211229205108.26373-25-straube.linux@gmail.com


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