spa: support: do not include C source file

Previously, `log-patterns.c` was included in two other source files
(`journal.c` and `logger.c`). It was also specified in the sources
list for the libspa-support library, which resulted in the unnecessary
independent compilation of the file, generating "defined but not used"
warnings.

Extract the function definitions into `log-patterns.h` and
use that in `journal.c` and `logger.c`, and remove the inclusion
of `log-patterns.c` from both.

spa/plugins/support/logger.c

@@ -40,6 +40,8 @@
 #include <spa/utils/string.h>
 #include <spa/utils/ansi.h>
 
+#include "log-patterns.h"
+
 #ifdef __FreeBSD__
 #define CLOCK_MONOTONIC_RAW CLOCK_MONOTONIC
 #endif
@@ -50,8 +52,6 @@
 
 #define TRACE_BUFFER (16*1024)
 
-#include "log-patterns.c"
-
 struct impl {
 	struct spa_handle handle;
 	struct spa_log log;