arm: socfpga: agilex5: Add warm reset mask for Agilex5

arm: socfpga: agilex5: Add warm reset mask for Agilex5

There are 5 L4 watchdogs and one SDM triggered warm reset bit
in Agilex5 reset manager "stat" register where bit 16:20 for L4
watchdogs. Assigning value 1 to these bits in the register address
will initiate SDM to trigger warm reset.

Introducing new warm reset mask for Agilex5 to trigger warm reset
to all five L4 watchdogs.

Signed-off-by: Tien Fong Chee <tien.fong.chee@altera.com>
Signed-off-by: Alif Zakuan Yuslaimi <alif.zakuan.yuslaimi@altera.com>
Reviewed-by: Tien Fong Chee <tien.fong.chee@altera.com>