ARM: at91: PIT: Use of_have_populated_dt instead of CONFIG_OF

ARM: at91: PIT: Use of_have_populated_dt instead of CONFIG_OF

Until now, the machines, even when CONFIG_OF was enabled, were calling
at91sam926x_ioremap_pit to try to map the PIT address using the defined
physical address.

Obviously, with DT, it's not appropriate anymore, and some code was added to
the function to deal with this case.

Unfortunately, this code was conditionned on CONFIG_OF, which can be enabled,
even though no DT was actually used, which would result in such a case, to this
code being executed, without any reason.

Moreover, the logic that was here before to bail out of the function just check
in the DT to see if the PIT node is there, which is the case in all our DTSI.

All this can be made much more straightforward just by using
of_have_populated_dt to bail out.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>