pldm: add service file

openbmc/pldm now has an in-repo systemd service file. Package the same.
Also need the srcrev bump with this commit because the two are co-reqs.

Signed-off-by: Deepak Kodihalli <dkodihal@in.ibm.com>
Change-Id: If9ec14c037772f15b079f2955894be24aa0b61b6
diff --git a/recipes-phosphor/pldm/pldm.inc b/recipes-phosphor/pldm/pldm.inc
index 7c09f10..421378b 100644
--- a/recipes-phosphor/pldm/pldm.inc
+++ b/recipes-phosphor/pldm/pldm.inc
@@ -2,4 +2,4 @@
 LICENSE = "Apache-2.0"
 LIC_FILES_CHKSUM = "file://LICENSE;md5=86d3f3a95c324c9479bd8986968f4327"
 SRC_URI = "git://github.com/openbmc/pldm"
-SRCREV = "250c47544a214b7e2f35a5688973f9c9cb1f7639"
+SRCREV = "4548c62553258301da2f0e7b10c26bac6910d53d"