meta-openpower: Bump pflash version to 5.2.1

No major changes.

Upstream now carries the patch we had in tree, so that can go.

Signed-off-by: Joel Stanley <joel@jms.id.au>
diff --git a/meta-openbmc-machines/meta-openpower/common/recipes-bsp/pflash/pflash.bb b/meta-openbmc-machines/meta-openpower/common/recipes-bsp/pflash/pflash.bb
index 6c2b0b6..5c0cfa4 100644
--- a/meta-openbmc-machines/meta-openpower/common/recipes-bsp/pflash/pflash.bb
+++ b/meta-openbmc-machines/meta-openpower/common/recipes-bsp/pflash/pflash.bb
@@ -6,9 +6,8 @@
 SRC_URI += "git://github.com/open-power/skiboot.git"
 LIC_FILES_CHKSUM = "file://${S}/LICENCE;md5=3b83ef96387f14655fc854ddc3c6bd57"
 
-SRCREV = "skiboot-5.2.0"
-PV = "5.2.0"
-SRC_URI += "file://0001-pflash-Allow-building-under-yocto.patch"
+SRCREV = "skiboot-5.2.1"
+PV = "5.2.1"
 
 S = "${WORKDIR}/git"