petalinux.conf: Updating SANITY_TESTED_DISTROS
petalinux.conf: Updating SANITY_TESTED_DISTROS

Removing redhat 7.2, 7.3 and adding 7.6, 7.7 as sanity tested distros

Signed-off-by: Jaewon Lee <1b369288d13b7b5cc9a37dd614e864b90fd18321@xilinx.com>

Xilinx/meta-petalinux,Xilinx/meta-petalinux,Xilinx/meta-petalinux,Xilinx/meta-petalinux,Xilinx/meta-petalinux,Xilinx/meta-petalinux