regulator: fan53555: change initcall level for early probe

ACPU clock driver initialization has dependency on regulator driver
initialization. The cpufreq driver requires the ACPU clock handle which
in turn requires the APC regulator handle.

In commit cf54c951 ("clock-a7/krait:
Change initcall level for early probe"), the cpufreq driver was modified
to use subsys_initcall level and ACPU clock driver changed to use
arch_initcall level. Change fan53555 regulator driver to arch_initcall
level to make sure the cpufreq driver can probe successfully.

Change-Id: I0914648c04f50dd542ed872aaa76afe674607546
Signed-off-by: Fenglin Wu <fenglinw@codeaurora.org>