drm: samsung: trigger emergency reboot if fail to set PLL_EN

Scandump doesn't record the right timing after receiving itmon error.
Trigger emergency reboot to ensure the issue timing.

Bug: 279094593
Test: trigger ramdump by hard code
Change-Id: I3da1f5febd335de8ffaf472b7fb27ff5c76ba61e
Signed-off-by: Ken Huang <kenbshuang@google.com>