requester: Remove related deprecated APIs

These have been deprecated for quite some time, and the last user
affecting OpenBMC CI has been dealt with.

Change-Id: I35d624d08e6a1b4ddc89bceca1b0e28ab4c98800
Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>
diff --git a/src/requester/meson.build b/src/requester/meson.build
index 77945f9..1a05f9a 100644
--- a/src/requester/meson.build
+++ b/src/requester/meson.build
@@ -1 +1 @@
-libpldm_sources += files('instance-id.c', 'pldm.c')
+libpldm_sources += files('instance-id.c')