i965/fs: Make emit_shader_time_write return rather than emit.

i965/fs: Make emit_shader_time_write return rather than emit.

Instead of emit_shader_time_write, we now do emit(SHADER_TIME_ADD(...)).
The advantage is that we can also insert a shader time write at an
arbitrary location in the instruction stream, rather than being
restricted to emitting at the end.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Topi Pohjolainen <topi.pohjolainen@intel.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Cc: mesa-stable@lists.freedesktop.org