clocksource/drivers/exynos_mct: Refactor resources allocation

clocksource/drivers/exynos_mct: Refactor resources allocation

Move interrupts allocation from exynos4_timer_resources() into separate
function together with the interrupt number parsing code from
mct_init_dt(), so the code for managing interrupts is kept together.
While touching exynos4_timer_resources() function, move of_iomap() to it.
No functional changes.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Tested-by: Chanwoo Choi <cw00.choi@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Link: https://lore.kernel.org/r/20211101193531.15078-2-semen.protsenko@linaro.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>