HomeScreen rotated to landscape mode on DRA7xx-EVM

After the workaround or fix for SPEC-798 is applied, the HomeScreen comes up in landscape mode on DRA7xx-EVM's LCD. This is due to the rework from SPEC-477 which broke DRA7xx-EVM's weston.ini file. The DRA7xx-EVM specific changes now have to be moved from the BSP specific layer bbappend to the centralized weston-ini-conf recipe. Otherwise the generic weston-ini-conf recipe just dumps out a default weston.ini for an HDMI display which does not apply to DRA7xx-EVM.