mb/intel/adlrvp: Refactor ADLRVP code to get rid of 'variants/baseboard'

List of changes:
1. Use devicetree.cb from default location
2. Create variant directory for ADL RVP with external EC as
'adlrvp_p_ext_ec'
3. Add initial overridetree.cb for 'adlrvp_p' and 'adlrvp_p_ext_ec'
to override 'devicetree.cb' as applicable.
4. Move all common files between 'adlrvp_p' and 'adlrvp_p_ext_ec'
to mainboard directory

TEST=Build and boot both ADLRVP with onboard and external EC.

Change-Id: I3591e214ed32dc9baaa49b92dff59579f29c7bd6
Signed-off-by: Subrata Banik <subrata.banik@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47335
Reviewed-by: V Sowmya <v.sowmya@intel.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

0 files changed, 0 insertions, 0 deletions