userspace: Add option for executing userspace module IPC in DP thread

Add a Kconfig option SOF_USERSPACE_MOD_IPC_BY_DP_THREAD that enables
processing IPC requests for a userspace module by its DP thread instead of
the shared user worker thread.

Set the option to default y when SOF_USERSPACE_APPLICATION is enabled,
where IPC requests are already processed by the module's DP thread by
default.

Signed-off-by: Adrian Warecki <adrian.warecki@intel.com>

Author: softwarecki

zephyr/Kconfig

@@ -123,6 +123,14 @@ config SOF_USERSPACE_PROXY
 	  It is responsible for forwarding module function calls coming from sof running in
 	  kernelspace to the module code executed with user privileges.
 
+config SOF_USERSPACE_MOD_IPC_BY_DP_THREAD
+	bool "Use userspace proxy to support userspace modules"
+	depends on USERSPACE
+	default y if SOF_USERSPACE_APPLICATION
+	help
+	  When enabled, IPC requests targeted to a userspace module are executed
+	  in its DP thread instead of the shared user worker thread.
+
 config SOF_USERSPACE_PROXY_WORKER_STACK_SIZE
 	int "Userspace IPC worker stack size"
 	default 4096