app: overlays: ptl: increased LL user-space heap

Bump the LL heap size of 0x8000 (512 KiB). This is current maximum
with CONFIG_VIRTUAL_HEAP (enabled by default for PTL).

Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>

Author: kv2019i

app/overlays/ptl/ll_userspace_overlay.conf

@@ -37,3 +37,9 @@ CONFIG_CROSS_CORE_STREAM=n
 CONFIG_INTEL_ADSP_MIC_PRIVACY=n
 CONFIG_XRUN_NOTIFICATIONS_ENABLE=n
 CONFIG_ZEPHYR_DP_SCHEDULER=n
+
+# Extend the shared LL user-space heap to 512KiB. This
+# is current maximum for PTL builds with virtual heap
+# enabled and uses the vmh allocation intended for KBP.
+# TODO: needs some better solution to allocate
+CONFIG_SOF_ZEPHYR_SYS_USER_HEAP_SIZE=0x80000