time: Add T_First constant The constant can be used to initialize variables of type HW.Time.T. Change-Id: I65246d6776d464bfa8648075b48e7de61cd82902 Signed-off-by: Adrian-Ken Rueegsegger <[email protected]> Reviewed-on: https://review.coreboot.org/c/libhwbase/+/38983 Tested-by: Nico Huber <[email protected]> Reviewed-by: Nico Huber <[email protected]>