xfs: Use kmem_free() instead of free()

This fixes a build failure caused by calling the free() function which
does not exist in the Linux kernel.

Signed-off-by: Thierry Reding <[e-mail]>
Reviewed-by: Mark Tinguely <[e-mail]>
Signed-off-by: Ben Myers <[e-mail]>

fs/xfs/xfs_log_recover.c

···
 		"bad number of regions (%d) in inode log format",
 				  in_f->ilf_size);
 			ASSERT(0);
-			free(ptr);
+			kmem_free(ptr);
 			return XFS_ERROR(EIO);
 		}