linux: Fix uninitialized variables

In file included from ../src/nvme/linux.c:40:
In function ‘freep’,
    inlined from ‘nvme_get_telemetry_log’ at ../src/nvme/linux.c:169:23:
../src/nvme/cleanup.h:24:9: warning: ‘log’ may be used uninitialized [-Wmaybe-uninitialized]
   24 |         free(*(void **)p);
      |         ^~~~~~~~~~~~~~~~~
../src/nvme/linux.c: In function ‘nvme_get_telemetry_log’:
../src/nvme/linux.c:169:30: note: ‘log’ was declared here
  169 |         _cleanup_free_ void *log;
      |                              ^~~

Signed-off-by: Tomas Bzatek <tbzatek@redhat.com>

src/nvme/linux.c

@@ -166,7 +166,7 @@ int nvme_get_telemetry_log(int fd, bool create, bool ctrl, bool rae, size_t max_
 
 	struct nvme_telemetry_log *telem;
 	enum nvme_cmd_get_log_lid lid;
-	_cleanup_free_ void *log;
+	_cleanup_free_ void *log = NULL;
 	void *tmp;
 	int err;
 	size_t dalb;