pdbg.bb: bump version

The revision fixes the pdbg issue on Romulus

Change-Id: Idd96ad49a0951bffa59930514d1d08012ae9702d
Signed-off-by: Lei YU <mine260309@gmail.com>
diff --git a/meta-openbmc-machines/meta-openpower/common/recipes-bsp/pdbg/pdbg.bb b/meta-openbmc-machines/meta-openpower/common/recipes-bsp/pdbg/pdbg.bb
index 3b00e04..2303c75 100644
--- a/meta-openbmc-machines/meta-openpower/common/recipes-bsp/pdbg/pdbg.bb
+++ b/meta-openbmc-machines/meta-openpower/common/recipes-bsp/pdbg/pdbg.bb
@@ -6,7 +6,7 @@
 SRC_URI += "git://github.com/open-power/pdbg.git"
 SRC_URI += "file://0001-CFAM-reg-0x2918-access-hack.patch"
 
-SRCREV = "6554a4a6bf73c22766650977eec07f90502b7438"
+SRCREV = "4b1c617f2a469e7033b3376a1b591f26c5010787"
 PV = "git${SRCREV}"
 
 S = "${WORKDIR}/git"