soc/intel_adsp_cavs15: Unbreak newlib linkage

In commit efa05d1e42da ("soc/intel_adsp: Put initial stack into the
CPU0 interrupt stack") the "_end" symbol was accidentally removed from
the linker script.  Newlib needs this to size its heap.

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
1 file changed