References to time members in CFE_FS_Header_t should be converted to CFE_TIME_SysTime_t

[thnkslprpt]

Describe the bug
cFE PR nasa/cFE#2246 converts all remaining seconds/subseconds time struct members to use CFE_TIME_SysTime_t that were not already doing so.
elf2cfetbl requires some updates as it references one of them directly (for cFE FS) in a few locations.

Code snips

elf2cfetbl/elf2cfetbl.c

Lines 2528 to 2536 in 46b29f8

	if (EnableTimeTagInHeader)
	{
	FileHeader.TimeSeconds = SrcFileTimeInScEpoch;
	FileHeader.TimeSubSeconds = 0;
	}
	else
	{
	FileHeader.TimeSeconds = 0;
	FileHeader.TimeSubSeconds = 0;

Expected behavior
Needs to be updated to reference the time members through the CFE_TIME_SysTime_t sub-struct.

Reporter Info
Avi Weiss @thnkslprpt