glsl: fix emit_inline_matrix_constructor for doubles
glsl: fix emit_inline_matrix_constructor for doubles

Specifically, for the case where we initialize a dmat with a source
matrix that has fewer columns/rows.

Reviewed-by: Kenneth Graunke <bd2562f754ec92342f93f61c25d731e290a2ffa8@whitecape.org>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler