Make target for timer.h (Kata on OpenTitan)
Make target for timer.h (Kata on OpenTitan)

This generates register definitions assuming two timers (-t 2) for each
of two harts (-s 2).

It also includes some Makefile readability cleanup for all of the
related register definition headers.

Change-Id: If6ea24c4bf628816af9f920eef1d68f5ac962ee7
GitOrigin-RevId: 197b5774d496b754f4ee3684085d87f6097ae388

AmbiML/sparrow-build