[Bugfix][API-1276]fix after flash_erase spm and reboot, fota cant switch slot

Only Configure: No
Affected branch: GSW3.0-no-common
Affected module: fota
Is it affected on both ZXIC and MTK: only MTK
Self-test: Yes
Doc Update: No

Change-Id: I597c2188513175474788491a83d1d84f7d4e6c87
1 file changed