kernel: mmu: exclude some funcs from coverage
kernel: mmu: exclude some funcs from coverage

page_frame_dump() and z_page_frames_dump() are used for
debug print, so there is no need to cover those funcs.
__weak function is also excluded, every test overrides it.

Signed-off-by: Lixin Guo <8de84fecf2daa12e9dd27dd0d7f47ee7775a73c0@intel.com>

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