reset upstream subtrees to HEAD

Reset the following subtrees on HEAD:
  poky: 8217b477a1(master)
  meta-xilinx: 64aa3d35ae(master)
  meta-openembedded: 0435c9e193(master)
  meta-raspberrypi: 490a4441ac(master)
  meta-security: cb6d1c85ee(master)

Squashed patches:
  meta-phosphor: drop systemd 239 patches
  meta-phosphor: mrw-api: use correct install path

Change-Id: I268e2646d9174ad305630c6bbd3fbc1a6105f43d
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/meta-openembedded/meta-oe/recipes-support/libiio/libiio_git.bb b/meta-openembedded/meta-oe/recipes-support/libiio/libiio_git.bb
index fa6f4c2..cc0efcc 100644
--- a/meta-openembedded/meta-oe/recipes-support/libiio/libiio_git.bb
+++ b/meta-openembedded/meta-oe/recipes-support/libiio/libiio_git.bb
@@ -4,8 +4,8 @@
 LICENSE = "LGPLv2.1+"
 LIC_FILES_CHKSUM = "file://COPYING.txt;md5=7c13b3376cea0ce68d2d2da0a1b3a72c"
 
-SRCREV = "fa82974d8bd1fded78e630ab71a7ded1b11d0e33"
-PV = "0.14+git${SRCPV}"
+SRCREV = "6ecff5d46e1b12c2859f0b63a73282940e3402bb"
+PV = "0.15+git${SRCPV}"
 
 SRC_URI = "git://github.com/analogdevicesinc/libiio.git;protocol=https"