r600/sfn: Don't clear clear group flag on vec4 that comes from TEX or FETCH

r600/sfn: Don't clear clear group flag on vec4 that comes from TEX or FETCH

If we consider clearing the group flag of a vec4 register that is used as
source for some instruction we have to take into account that the parent
of the register element may also be part of a group in the parent instruction.
In this case we must not clear the group flag.

Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/9118

Fixes:  f3415cb26a (r600/sfn: copy propagate register load chains)

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23813>