Avoid multiple returns and possible uninitialized variable warning in CFE_TIME_RegisterSynchCallback

[skliper]

Is your feature request related to a problem? Please describe.
Multiple returns and an (invalid) possible uninitialized variable warning shows up from static analysis:

cFE/fsw/cfe-core/src/time/cfe_time_api.c

Lines 758 to 786 in 56397a3

	int32 CFE_TIME_RegisterSynchCallback(CFE_TIME_SynchCallbackPtr_t CallbackFuncPtr)
	{
	int32 Status;
	CFE_ES_ResourceID_t AppId;
	uint32 AppIndex;
	Status = CFE_ES_GetAppID(&AppId);
	if (Status == CFE_SUCCESS)
	{
	Status = CFE_ES_AppID_ToIndex(AppId, &AppIndex);
	}
	if (Status != CFE_SUCCESS)
	{
	/* Called from an invalid context */
	return Status;
	}
	if (AppIndex >= (sizeof(CFE_TIME_TaskData.SynchCallback) / sizeof(CFE_TIME_TaskData.SynchCallback[0])) ||
	CFE_TIME_TaskData.SynchCallback[AppIndex].Ptr != NULL)
	{
	Status = CFE_TIME_TOO_MANY_SYNCH_CALLBACKS;
	}
	else
	{
	CFE_TIME_TaskData.SynchCallback[AppIndex].Ptr = CallbackFuncPtr;
	}
	return Status;
	} /* End of CFE_TIME_RegisterSynchCallback() */

Describe the solution you'd like
Refactor for one return and avoid warning.

Describe alternatives you've considered
Leave as is (works)

Additional context
None

Requester Info
Jacob Hageman - NASA/GSFC