vgaarb: remove vga_conflicts

vga_conflicts only has a single caller and none of the arch overrides
mentioned in the comment.  Just remove it and the thus dead check in the
caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20210716061634.2446357-3-hch@lst.de


Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>