Bug fix when building pldm with oem-ibm diabled

Fixed issues that were seen when trying to build pldm with "oem-ibm"
disabled. Changed both the meson.build and pldmtool.cpp file to check
for the "oem-ibm" option.

Signed-off-by: Zahed Hossain <zahzahed@in.ibm.com>
Change-Id: If052cb6b8ff4dbb11d25ec2d0c0ea7828de3b0da
diff --git a/tool/pldmtool.cpp b/tool/pldmtool.cpp
index bbb222d..22cdd6b 100644
--- a/tool/pldmtool.cpp
+++ b/tool/pldmtool.cpp
@@ -73,7 +73,10 @@
     pldmtool::bios::registerCommand(app);
     pldmtool::platform::registerCommand(app);
     pldmtool::fru::registerCommand(app);
+
+#ifdef OEM_IBM
     pldmtool::oem_ibm::power_host::registerCommand(app);
+#endif
 
     CLI11_PARSE(app, argc, argv);
     return 0;