Write back group setting to original at 72-pvr-seat.rule

Write back group setting to original at 72-pvr-seat.rule

The access permission of /dev/pvr_sync is set group=display by
72-pvr-seat.rule.  This setting replace from video to display at
meta-agl/meta-agl-bsp/meta-rcar-gen3/recipes-graphics/
gles-module/gles-user-module.bbappend.
This change is not necessary in current AGL IVI demo.
Because the similar device files set video group such as /dev/dri/cardX.

This patch write back group setting to original at 72-pvr-seat.rule.

Bug-AGL: SPEC-4777

Change-Id: I2bfbd8f387876207f2d09ee9e84eced61ada0904
Signed-off-by: Naoto Yamaguchi <naoto.yamaguchi@aisin.co.jp>