power: smb1360: Move the time consuming initialization to a worker thread

Specific delay is needed after SMB1360 power on, FG reset, or waiting for
FG memory access being granted. These time consuming operations in the
driver probe() function will slow down the kernel initial process and
result a long boot up time.

Move time consuming initialization into a delay worker, and replace the
FG memory access granted status polling by using the FG access granted
interrupt.

CRs-Fixed: 829505
Change-Id: I8f3dccbf40d111f82fa63650c2cc1f26a090665c
Signed-off-by: Fenglin Wu <fenglinw@codeaurora.org>