counter: Introduce the compare component

Compare registers are used in devices to compare a counter channel
against a particular count value (e.g. to check if a threshold has been
reached). A macro COUNTER_COMP_COMPARE() is introduced to facilitate the
creation of compare components as Count extensions.

Link: https://lore.kernel.org/r/20250306-introduce-compare-component-v1-1-93993b3dca9c@kernel.org


Signed-off-by: William Breathitt Gray <wbg@kernel.org>