makefile: add phony am--refresh target
makefile: add phony am--refresh target

for some reason when I configure --with-dri-drivers="" the src/mesa/drivers/dri
Makefile tries to call the am--refresh target in the toplevel Makefile,
we don't have one, and I'm not sure what it should look like.

This makes things continue on.

Signed-off-by: Dave Airlie <f2295d84e358395675bc8031be58672073ae065e@redhat.com>

tokyovigilante/glsl-optimizer,zz85/glsl-optimizer,benaadams/glsl-optimizer,tokyovigilante/glsl-optimizer,zz85/glsl-optimizer,bkaradzic/glsl-optimizer,mcanthony/glsl-optimizer,zz85/glsl-optimizer,mapbox/glsl-optimizer,dellis1972/glsl-optimizer,benaadams/glsl-optimizer,wolf96/glsl-optimizer,wolf96/glsl-optimizer,mcanthony/glsl-optimizer,dellis1972/glsl-optimizer,mapbox/glsl-optimizer,bkaradzic/glsl-optimizer,bkaradzic/glsl-optimizer,djreep81/glsl-optimizer,jbarczak/glsl-optimizer,benaadams/glsl-optimizer,jbarczak/glsl-optimizer,mapbox/glsl-optimizer,zz85/glsl-optimizer,bkaradzic/glsl-optimizer,jbarczak/glsl-optimizer,jbarczak/glsl-optimizer,zeux/glsl-optimizer,benaadams/glsl-optimizer,mapbox/glsl-optimizer,zz85/glsl-optimizer,djreep81/glsl-optimizer,mapbox/glsl-optimizer,wolf96/glsl-optimizer,mcanthony/glsl-optimizer,zeux/glsl-optimizer,mcanthony/glsl-optimizer,zeux/glsl-optimizer,tokyovigilante/glsl-optimizer,metora/MesaGLSLCompiler,bkaradzic/glsl-optimizer,dellis1972/glsl-optimizer,benaadams/glsl-optimizer,benaadams/glsl-optimizer,dellis1972/glsl-optimizer,djreep81/glsl-optimizer,djreep81/glsl-optimizer,tokyovigilante/glsl-optimizer,metora/MesaGLSLCompiler,mcanthony/glsl-optimizer,jbarczak/glsl-optimizer,zeux/glsl-optimizer,zeux/glsl-optimizer,wolf96/glsl-optimizer,wolf96/glsl-optimizer,dellis1972/glsl-optimizer,zz85/glsl-optimizer,metora/MesaGLSLCompiler,tokyovigilante/glsl-optimizer,djreep81/glsl-optimizer