SAMA5D2 and SAMA5D4 does not support external reset.
Some SAMA5 board's Kconfig contain item SAMA5_SYSTEMRESET, but it is better in arch/arm/src/Kconfig.
since the code could map the unsupported work to the
supported one and remove select SCHED_WORKQUEUE from
Kconfig since SCHED_[L|H]PWORK already do the selection
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>