ima: remove redundant initialization of pointer 'file'.

The pointer 'file' is being initialized with a value that is never read,
it is being re-assigned the same value later on closer to where it is
being first used. The initialization is redundant and can be removed.

Cleans up clang scan build warning:
security/integrity/ima/ima_main.c:434:15: warning: Value stored to 'file'
during its initialization is never read [deadcode.DeadStores]
Signed-off-by: NColin Ian King <colin.i.king@gmail.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

security/integrity/ima/ima_main.c

@@ -432,7 +432,7 @@ int ima_file_mmap(struct file *file, unsigned long prot)
 int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot)
 {
 	struct ima_template_desc *template = NULL;
-	struct file *file = vma->vm_file;
+	struct file *file;
 	char filename[NAME_MAX];
 	char *pathbuf = NULL;
 	const char *pathname = NULL;