app_memdomain: ARC: adjust asembler directives for MWDT toolchain
app_memdomain: ARC: adjust asembler directives for MWDT toolchain

ARC MWDT assembler has slightly different directives names:
.pushsect instead of .pushsection
.popsect instead of .popsection

Signed-off-by: Eugeniy Paltsev <ec089b543c2604b626d7ce60c03e4d074ed102c7@synopsys.com>

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