zephyr: remove unnecessary Kconfig defaults

Remove unnecessary 'n' defaults in sof/zephyr Kconfig. This doesn't affect
any current build as 'n' is the default if not set otherwise.

By removing the unconditional defaults, it becomes possible to set
defaults later in board/family specific Kconfig.defconfig files.

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

Author: kv2019i

zephyr/Kconfig

@@ -2,7 +2,6 @@ if SOF
 
 config SOF_STAGING
 	bool "Enable SOF staging features and modules"
-	default n
 	help
 	  SOF staging features are not ready for production but are
 	  upstream to enable developers to continue development in order
@@ -13,7 +12,6 @@ rsource "../Kconfig.sof"
 
 config SOF_USERSPACE
 	bool "Enable SOF support for userspace modules"
-	default n
 	help
 	  SOF userspace modules support will enable modules to run in DP
 	  processing mode as userspace code and data. This feature is WIP
@@ -22,7 +20,6 @@ config SOF_USERSPACE
 config SOF_ZEPHYR_HEAP_CACHED
 	bool "Cached Zephyr heap for SOF memory non-shared zones"
 	default y if CAVS || ACE
-	default n
 	help
 	  Enable cached heap by mapping cached SOF memory zones to different
 	  Zephyr sys_heap objects and enable caching for non-shared zones.
@@ -81,7 +78,6 @@ config SOF_ZEPHYR_USERSPACE_MODULE_HEAP_SIZE
 
 config ZEPHYR_NATIVE_DRIVERS
 	bool "Use Zephyr native drivers"
-	default n
 	help
 	  Enable Zephyr native api drivers for host and dai audio components
 	  host-zephyr
@@ -113,7 +109,6 @@ config PIPELINE_2_0
 config ZEPHYR_DP_SCHEDULER
 	bool "use Zephyr thread based DP scheduler"
 	default y if ACE
-	default n
 	depends on IPC_MAJOR_4
 	depends on ZEPHYR_SOF_MODULE
 	depends on ACE
@@ -155,7 +150,6 @@ config SOF_ZEPHYR_NO_SOF_CLOCK
 config VIRTUAL_HEAP
 	bool "Use virtual memory heap to allocate a buffers"
 	default y if ACE
-	default n
 	depends on ACE
 	help
 	  Enabling this option will use the virtual memory heap allocator to allocate buffers.