lima/ppir: Add gl_PointCoord handling

Treat gl_PointCoord as a system value and
add the necessary bits for correct codegen.

Signed-off-by: Andreas Baierl <ichgeh@imkreisrum.de>
Reviewed-by: Qiang Yu <yuq825@gmail.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
13 jobs for !988 with gl_PointCoord in 10 minutes and 4 seconds (queued for 43 seconds)
detached
Status Job ID Name Coverage
  Containers Build
passed #430706
debian

00:00:19

 
  Build+Test
passed #430715
meson-arm64

00:02:11

passed #430714
meson-armhf

00:02:40

passed #430708
meson-clang

00:08:52

passed #430712
meson-clover

00:09:44

passed #430716
meson-i386

00:01:51

passed #430711
meson-main

00:06:00

passed #430707
meson-swr-glvnd

00:06:41

passed #430713
meson-vulkan

00:03:45

passed #430718
scons-llvm

00:04:09

passed #430717
scons-nollvm

00:02:59

passed #430709
scons-swr

00:06:18

passed #430710
scons-win64

00:06:48