arm64: configs: Add PANIC_TIMEOUT to 5 sec

arm64: configs: Add PANIC_TIMEOUT to 5 sec

Panic timeout was not set for HE and so device was waiting for
WDT to reset the system in case of kernel panic.

Added the panic timeout to 5 sec.

boot.img size not changed.

Bug 200171082

Change-Id: If562f81b3673abe0c841bda8b06a785ac6d03dfe
Signed-off-by: Gagan Grover <ggrover@nvidia.com>
Reviewed-on: http://git-master/r/1018096
(cherry picked from commit 7778da11788824d078267c8c8fd3175dabfae971)
Reviewed-on: http://git-master/r/1020379
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>