clocksource/drivers/timer-integrator-ap: Add missing Kconfig dependency on OF

clocksource/drivers/timer-integrator-ap: Add missing Kconfig dependency on OF

This driver accesses the of_aliases global variable declared in
linux/of.h and defined in drivers/base/of.c. It requires OF support or
will cause a link failure. Add the missing Kconfig dependency.

Closes: https://lore.kernel.org/oe-kbuild-all/202601152233.og6LdeUo-lkp@intel.com/
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://patch.msgid.link/20260116111723.10585-1-bartosz.golaszewski@oss.qualcomm.com