Remove ASSERT within Ls for RTC error and associated changes.

Remove ASSERT within Ls for RTC error and associated changes.

TimeDate.c: replace magic number with constant.
Ls.c: use new warning printout string and remove an ASSERT.  also replace magic number with constant.
The UNI file: add new warning printout string.

Signed-off-by: jcarsey
Reviewed-by: geekboy15a
Reviewed-by: lgrosenb
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@11703 6f19259b-4bc3-4df7-8a09-765794883524