vgaarb: Remove unneeded semicolons

Remove superfluous semicolons after function definitions.

Signed-off-by: Yue Zou <zouyue3@huawei.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210118010356.214491-1-zouyue3@huawei.com