fbdev: vermilion: decrease reference count in error path

pci_get_device() will increase the reference count for the returned
pci_dev. For the error path, we need to use pci_dev_put() to decrease
the reference count.

Fixes: dbe7e429 ("vmlfb: framebuffer driver for Intel Vermilion Range")
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Signed-off-by: Helge Deller <deller@gmx.de>