soc: intel_s1000: add _heap_sentry to linker script

Newlib requires a _heap_sentry so we add it to the linker script,
similar to what other xtensa linker scripts.

Signed-off-by: Daniel Leung <[email protected]>

Author: dcpleung

soc/xtensa/intel_s1000/linker.ld

@@ -442,6 +442,7 @@ SECTIONS
     *(.dma_buffers)
     _dma_buf_end = ABSOLUTE(.);
   } >LPRAM_REGION
+  _heap_sentry = DT_L2_SRAM_BASE + DT_L2_SRAM_SIZE;
   .comment  0 :  { *(.comment) }
   .debug 0 : { *(.debug) }
   .line 0 : { *(.line) }