intel/compiler: Make component() work for FIXED_GRF/ARF

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18157>

src/intel/compiler/brw_ir_fs.h

@@ -164,6 +164,11 @@ component(fs_reg reg, unsigned idx)
 {
    reg = horiz_offset(reg, idx);
    reg.stride = 0;
+   if (reg.file == ARF || reg.file == FIXED_GRF) {
+      reg.vstride = BRW_VERTICAL_STRIDE_0;
+      reg.width = BRW_WIDTH_1;
+      reg.hstride = BRW_HORIZONTAL_STRIDE_0;
+   }
    return reg;
 }