clocksource/drivers/dw_apb: Remove unused dw_apb_clockevent functions

clocksource/drivers/dw_apb: Remove unused dw_apb_clockevent functions

dw_apb_clockevent_pause(), dw_apb_clockevent_resume() and
dw_apb_clockevent_stop() have been unused since 2021's
commit 1b79fc4f2bfd ("x86/apb_timer: Remove driver for deprecated
platform")

Remove them.

(Some of the other clockevent functions are still called by
dw_apb_timer_of.c  so I guess it is still in use?)

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Link: https://lore.kernel.org/r/20241025203101.241709-1-linux@treblig.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>