btrfs-tools: upgrade 5.14.2 -> 5.15

Changelog v5.15 (Nov 2021)

mkfs: new defaults!
no-holes
free-space-tree
DUP for metadata unconditionally
libbtrfsutil: add missing profile defines
libbtrfs: minimize its impact on the other code, refactor and separate implementation where needed, cleanup afterwards, reduced header exports
documentation: introduce sphinx build and RST versions of manual pages, will become the new format and replace asciidoc
fixes: fix warning regarding v1 space cache when only v2 (free space tree) is enabled

(From OE-Core rev: 77d08d327b9e675109dc95c27ee4910d9047ec49)

Signed-off-by: Wang Mingyu <wangmy@fujitsu.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/btrfs-tools/btrfs-tools_5.15.bb

@@ -19,7 +19,7 @@ SRC_URI = "git://git.kernel.org/pub/scm/linux/kernel/git/kdave/btrfs-progs.git;b
            file://0001-Add-a-possibility-to-specify-where-python-modules-ar.patch \
            file://0001-btrfs-tools-include-linux-const.h-to-fix-build-with-.patch \
            "
-SRCREV = "35f17bc49cdf760d8f3710fe2c301b933d991fd6"
+SRCREV = "4d06e4a13d1ce1849a60b68969bc385ab736ddf7"
 S = "${WORKDIR}/git"
 
 PACKAGECONFIG ??= " \