arm: mach-k3: *: dev-data: Update to use ARRAY_SIZE

Instead of hard-coding the count of entries manually, use ARRAY_SIZE
to keep the count updates appropriately.

Cc: Bryan Brattlof <bb@ti.com>
Suggested-by: Ravi Gunasekaran <r-gunasekaran@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Bryan Brattlof <bb@ti.com>
Reviewed-by: Siddharth Vadapalli <s-vadapalli@ti.com>