spmi: spmi-pmic-arb-debug: Change the probe init order

Currently, both the regular and debug spmi pmic arbiter devices
are probed in the same initcall order (arch_init). This is fine.
However, most of the sepolicy rules set in the userspace are
for the PMIC devices under spmi-0 bus. If the debug spmi pmic
arbiter device probes first and takes "spmi-0" name, then the
sepolicy rules set will be broken. Fix it by changing the
probe init order of debug spmi pmic arbiter device to module
init.

Change-Id: I145e78a205bc80f274d8d926353a88255a7f4167
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>