doc: ARC: update ARC HW & tools support status
doc: ARC: update ARC HW & tools support status

List of the changes:
 * add info about ARCv3 32bit HS5x which support has been
   upstreamed recently
 * mark HS6x MWDT toolchain support as Y

Signed-off-by: Evgeniy Paltsev <7de4ab8b01334d64e4e84734c688a8a936513edc@gmail.com>
Signed-off-by: Eugeniy Paltsev <ec089b543c2604b626d7ce60c03e4d074ed102c7@synopsys.com>

zephyrproject-rtos/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,galak/zephyr,galak/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr