Revert "softpipe/buffer: load only as many components as the the buffer resource type provides"

This reverts commit 865b9dda.

The buffer always reports format PIPE_FORMAT_R8_UNORM so with this patch only
one component would be supported. The original issue is still relevant, but
the fix should be different.

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
(cherry picked from commit 0f598ed7)