r600/sfn: make number of source components a local variable

There is no need to keep that value as a member and it irritates
Coverity.

Fixes: 688680decce9
  r600/nir: fetch sources and split uniforms before emittting alu instructions

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6787>
2 files changed