video: fbdev: pvr2fb: fix link error for pvr2fb_pci_exit

When the driver is built-in for PCI, we reference the exit function
after discarding it:

`pvr2fb_pci_exit' referenced in section `.ref.data' of drivers/video/fbdev/pvr2fb.o: defined in discarded section `.exit.text' of drivers/video/fbdev/pvr2fb.o

Just remove the __exit annotation as the easiest workaround.

Also apply the same workaround for pvr2fb_dc_exit().

Fixes: 0f5a5712 ("video: fbdev: pvr2fb: add COMPILE_TEST support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: YueHaibing <yuehaibing@huawei.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
[b.zolnierkie: remove __exit annotation also from pvr2fb_dc_exit()]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>