Update swift mrw to latest version

A lot of cleanup of IPMI sensors in this update

Change-Id: I6316b877833d3e36f363e90ecca2884ace4b6ec2
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
diff --git a/meta-witherspoon/conf/machine/swift.conf b/meta-witherspoon/conf/machine/swift.conf
index 077d0b5..3915e2b 100644
--- a/meta-witherspoon/conf/machine/swift.conf
+++ b/meta-witherspoon/conf/machine/swift.conf
@@ -7,7 +7,7 @@
 PHOSPHOR_MRW_LICENSE = "Apache-2.0"
 PHOSPHOR_MRW_LIC_FILES_CHKSUM = "file://LICENSE;md5=e3fc50a88d0a364313df4b21ef20c29e"
 PHOSPHOR_MRW_URI = "git://git@github.com/open-power/swift-xml;protocol=ssh"
-PHOSPHOR_MRW_REV = "7880e778af3fca75f46aa3e94f7e9971a6ddbb1f"
+PHOSPHOR_MRW_REV = "2b59e12db44e167a1652777b770674d235ec55ba"
 
 # 128MB flash size
 FLASH_SIZE = "131072"