soc: intel_s1000_crb: fix XCC build error with newlib

The Newlib in the XCC toolchain for intel_s1000_crb has a few
missing functions which are reentrant versions of the one
defined in lib/libc/newlib/libc-hooks.c. So make these call
the correct functions.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>