drm/i915/psr: Move writing early transport pipe src

Currently PIPE_SRCSZ_ERLY_TPT is written in
intel_display.c:intel_set_pipe_src_size. This doesn't work as
intel_set_pipe_src_size is called only on modeset.

Bspec: 68927

Fixes: 3291bbb9

 ("drm/i915/psr: Configure PIPE_SRCSZ_ERLY_TPT for psr2 early transport")
Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
Reviewed-by: Mika Kahola <mika.kahola@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240319123327.1661097-3-jouni.hogander@intel.com
(cherry picked from commit b52c4093

)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>