staging: r8188eu: simplify odm_evm_db_to_percentage()

Use clamp() to simplify odm_evm_db_to_percentage().

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20210730090948.32759-3-straube.linux@gmail.com


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