viafbdev: fix compilation warning for unused variable

viafbdev: Fix compilation warning for unused variable for #ifdef MODULE
Fix compilation warning when #ifdef MODULE

drivers/video/via/viafbdev.c: In function ‘viafb_init’:
drivers/video/via/viafbdev.c:2019: warning: unused variable ‘r’

Signed-off-by: Nikanth Karthikesan <nikanth@google.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>