Add shutdown procedure for WL2868C and force disable all regulators when system power off to avoid unexpected current leakage. Change-Id: I4851e250460962867e27133452a9bbc9d6224a85 Signed-off-by: qiaopf1 <qiaopf1@motorola.com> Reviewed-on: https://gerrit.mot.com/2178320 SME-Granted: SME Approvals Granted SLTApproved: Slta Waiver Tested-by: Jira Key Reviewed-by: Long Cheng <chengl1@motorola.com> Reviewed-by: Zhichao Chen <chenzc2@motorola.com> Submit-Approved: Jira Key