usb-misc: sisusbvga: Fix coding style: remove assignment from if tests

The file drivers/usb/misc/sisusbvga/sisusb.c had 6 assignments inside if
tests. This patch move the assignment outside the test. The changes
also fix the remaining 2 lines that were over 80 characters.

Signed-off-by: Peter Senna Tschudin <peter.senna@collabora.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>