tests: logging: Allow LOG_PRINTK from user space

The commit '3b29b9fa3b4 (tests: logging: restore userspace testing,
2025-04-18)' set CONFIG_LOG_PRINTK=n which brakes the build on the
platform 'ip_k66f'.

Without CONFIG_LOG_PRINTK=n (dependency from CONFIG_USERSPACE=y) some
tests in 'tests/subsys/logging/log_core_additional/logging.log_user'
would not build.

Remove this dependency so that LOG_PRINTK can also be used from user
space, which is possible since '77925656ab8 (logging: Fix runtime
message creation in user-mode thread, 2025-04-18)' and reset
CONFIG_LOG_PRINTK=y.

Fixes: #89067
Signed-off-by: Christoph Winklhofer <cj.winklhofer@gmail.com>

Author: cjwinklhofer

subsys/logging/Kconfig.processing

@@ -7,7 +7,6 @@ if !LOG_MODE_MINIMAL
 
 config LOG_PRINTK
 	bool "Process printk messages"
-	depends on !USERSPACE
 	default y if PRINTK
 	help
 	  If enabled, printk messages are redirected to the logging subsystem.

tests/subsys/logging/log_core_additional/log_user.conf

@@ -9,7 +9,7 @@ CONFIG_LOG_ALWAYS_RUNTIME=y
 CONFIG_LOG_PROCESS_THREAD=n
 CONFIG_LOG_PROCESS_TRIGGER_THRESHOLD=1
 CONFIG_THREAD_MONITOR=y
-CONFIG_LOG_PRINTK=n
+CONFIG_LOG_PRINTK=y
 CONFIG_LOG_BLOCK_IN_THREAD=y
 CONFIG_MAIN_STACK_SIZE=4096
 CONFIG_STACK_SENTINEL=n

tests/subsys/logging/log_core_additional/src/log_test_user.c

@@ -83,4 +83,12 @@ ZTEST_USER(test_log_core_additional, test_log_panic)
 	log_panic();
 }
 
+/* test LOG_PRINTK from user space */
+ZTEST_USER(test_log_core_additional, test_log_printk_from_user)
+{
+	LOG_PRINTK("test_printk");
+	while (log_process()) {
+	}
+}
+
 #endif /** CONFIG_USERSPACE **/