xtensa: mmu: do not map heap if not using heap

Do not map the heap area by default if we are not using
heap at all.

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

Author: dcpleung

arch/xtensa/core/xtensa_mmu.c

@@ -133,6 +133,7 @@ static const struct xtensa_mmu_range mmu_zephyr_ranges[] = {
 #endif
 		.name = "data",
 	},
+#if CONFIG_HEAP_MEM_POOL_SIZE > 0
 	/* System heap memory */
 	{
 		.start = (uint32_t)_heap_start,
@@ -144,6 +145,7 @@ static const struct xtensa_mmu_range mmu_zephyr_ranges[] = {
 #endif
 		.name = "heap",
 	},
+#endif
 	/* Mark text segment cacheable, read only and executable */
 	{
 		.start = (uint32_t)__text_region_start,