meson: fix libpldm move to its own repository

The libpldm moved into its own repository separate from pldm proper.
Update the wrap file and meson.build accordingly.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I9559f361de3fb66a73ab6d18611ec34753377585
diff --git a/subprojects/libpldm.wrap b/subprojects/libpldm.wrap
new file mode 100644
index 0000000..5c90142
--- /dev/null
+++ b/subprojects/libpldm.wrap
@@ -0,0 +1,6 @@
+[wrap-git]
+url = https://github.com/openbmc/libpldm.git
+revision = HEAD
+
+[provide]
+libpldm = libpldm_dep