power: smb5: Fix a possible reverse boost

If a PD hard reset occurs while the device is charging with charge
pump (CP) enabled, SMB_EN pin will go low. After hard reset, it is
occasionally observed that the moment SMB_EN pin goes high, switcher
is already enabled, which causes reverse boost issue.

Disable the CP switcher during PD hard reset, and re-enable it
with some delay after SMB_EN pin goes high when the input is
present.

Change-Id: Ie8182ae9425367792327683436f01c9436d66e08
Signed-off-by: Harry Yang <harryy@codeaurora.org>