r600: Fix duplicated subexpression in r600_asm.c
Fixes: 4422ce1b r600: force new CF with TEX only if any texture value is written Closes #3012 Signed-off-by:Gert Wollny <gert.wollny@collabora.com> Part-of: <mesa/mesa!5187> (cherry picked from commit 901793d5)