[BUG] Compilation fails for i.MX8MP with Xtensa toolchain

[dbaluta]

Describe the bug

Using Xtensa proprietary toolchain based on xt-clang (Clang 10.0.1) compilation fails with following error

/home/bamboo/sof_dir/zephyr/drivers/timer/xtensa_sys_timer.c
In file included from /home/bamboo/sof_dir/zephyr/drivers/timer/xtensa_sys_timer.c:78:
/home/bamboo/sof_dir/zephyr/drivers/timer/system_timer_generic.h:312:30: error: use of undeclared identifier '__LONG_WIDTH__'
               (timer_core_cycles_t)TIMER_CORE_COUNTER_MASK;
                                    ^
/home/bamboo/sof_dir/zephyr/drivers/timer/system_timer_generic.h:217:54: note: expanded from macro 'TIMER_CORE_COUNTER_MASK'
#define TIMER_CORE_COUNTER_MASK (UINT64_MAX >> (64 - TIMER_CORE_COUNTER_WIDTH))
                                                     ^
/home/bamboo/sof_dir/zephyr/drivers/timer/system_timer_generic.h:213:34: note: expanded from macro 'TIMER_CORE_COUNTER_WIDTH'
#define TIMER_CORE_COUNTER_WIDTH __LONG_WIDTH__

To Reproduce

XTENSA_TOOLS_ROOT=~/work/repos/imx-audio-toolchain/Xtensa_Tool/ ./scripts/xtensa-build-zephyr.py -p imx8m

Reproduction Rate

100%

Expected behavior

Code should compile cleanly

Impact

Major, CI fails with no possibility to test further changes.

[dbaluta]

Possible fix here: zephyrproject-rtos/zephyr#118631