config/arm: add core and NUMA counts to cross files

config/arm: add core and NUMA counts to cross files

Add support for setting core count and numa nodes in cross files. The
values specified in cross files will override the default values.
Also add missing default values to Arm config.

Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Acked-by: Jerin Jacob <jerinj@marvell.com>
Tested-by: Jerin Jacob <jerinj@marvell.com>
Tested-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
Tested-by: Vimal Chungath <vcchunga@amazon.com>
Tested-by: Dharmik Thakkar <dharmik.thakkar@arm.com>