btrfs: remove struct find_free_extent.ram_bytes

This hasn't been used since it was first introduced in commit
b4bd745d ("btrfs: Introduce find_free_extent_ctl structure for later
rework"). Passing that to btrfs_add_reserved_bytes in find_free_extent
is not strictly necessary and using the local ram_bytes instead seems
cleaner.
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/extent-tree.c

@@ -3438,7 +3438,6 @@ btrfs_release_block_group(struct btrfs_block_group *cache,
  */
 struct find_free_extent_ctl {
 	/* Basic allocation info */
-	u64 ram_bytes;
 	u64 num_bytes;
 	u64 empty_size;
 	u64 flags;
@@ -3810,7 +3809,6 @@ static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
 
 	WARN_ON(num_bytes < fs_info->sectorsize);
 
-	ffe_ctl.ram_bytes = ram_bytes;
 	ffe_ctl.num_bytes = num_bytes;
 	ffe_ctl.empty_size = empty_size;
 	ffe_ctl.flags = flags;