Customer might have specific folder where stores their own configurations
for their customized scenario/board, so add TARGET_DIR parameter to support
option that build hyprvisor with specified configurations.
So valid usages are: (target = all | hypervisor)
1. make <target>
2. make <target> KCONFIG_FILE=xxx [TARGET_DIR=xxx]
3. make <target> BOARD=xxx SCENARIO=xxx [TARGET_DIR=xxx]
4. make <target> BOARD_FILE=xxx SCENARIO_FILE=xxx [TARGET_DIR=xxx]
5. make <target> KCONFIG_FILE=xxx BOARD_FILE=xxx SCENARIO_FILE=xxx [TARGET_DIR=xxx]
If TARGET_DIR parameter is not specified in make command, hypervisor will be
built with board configurations under hypervisor/arch/x86/configs/ and scenario
configurations under hypervisor/scenarios/. Moreover, the configurations would
be overwritten if BOARD/SCENARIO files are specified in make command.
If TARGET_DIR parameter is specified in make command, hypervisor will be built
with configuration under that folder if no BOARD/SCENARIO files are specified.
When BOARD/SCENARIO files are available in make command, the TARGET_DIR is used
to store configurations that BOARD/SCENARIO file provided, i.e. Configurations
in TARGET_DIR folder will be overwritten.
Tracked-On: #4517
Signed-off-by: Victor Sun <victor.sun@intel.com>