usb: misc: brcmstb-usb-pinmap: Make sync_all_pins static

usb: misc: brcmstb-usb-pinmap: Make sync_all_pins static

Fix the following sparse warning:

drivers/usb/misc/brcmstb-usb-pinmap.c:219:6: warning: symbol 'sync_all_pins' was not declared. Should it be static?

The sync_all_pins has only call site within brcmstb-usb-pinmap.c
It should be static

Fixes: 517c4c44b323 ("usb: Add driver to allow any GPIO to be used for 7211 USB signals")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zou Wei <zou_wei@huawei.com>
Link: https://lore.kernel.org/r/1604050097-91302-1-git-send-email-zou_wei@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>