cpu/ti/am335x: Extend monotonic timer to early stages

It is actually all completely broken, dmtimer.c is
not really implemented.

Change-Id: Ifb3f624930c9ef663fae30cd5ddcb1d3d46f06b1
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36593
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/cpu/ti/am335x/Makefile.inc

@@ -3,9 +3,12 @@ bootblock-y	+= bootblock_media.c
 bootblock-y	+= dmtimer.c
 bootblock-y	+= gpio.c
 bootblock-y	+= pinmux.c
+bootblock-y	+= monotonic_timer.c
 
 romstage-y	+= nand.c
 romstage-y	+= cbmem.c
+romstage-y	+= dmtimer.c
+romstage-y	+= monotonic_timer.c
 
 ramstage-y	+= dmtimer.c
 ramstage-y	+= monotonic_timer.c