meson: adjust nlohmann-json dependency

Simplify the meson dependency for nlohmann-json, use the consistent
dependency name, and align the wrap file name with other repositories.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I3a682a3e07e38d0a1bfe35858e24f1bb74b4ec34
diff --git a/meson.build b/meson.build
index 2e4d8fd..3430735 100644
--- a/meson.build
+++ b/meson.build
@@ -84,11 +84,7 @@
 stdplus = dependency('stdplus')
 phosphor_logging_dep = dependency('phosphor-logging')
 
-if cpp.has_header('nlohmann/json.hpp')
-  nlohmann_json = declare_dependency()
-else
-  nlohmann_json = dependency('nlohmann_json')
-endif
+nlohmann_json_dep = dependency('nlohmann_json', include_type: 'system')
 
 if cpp.has_header('CLI/CLI.hpp')
   CLI11_dep = declare_dependency()
@@ -146,7 +142,7 @@
       libpldm_dep,
       phosphor_dbus_interfaces,
       phosphor_logging_dep,
-      nlohmann_json,
+      nlohmann_json_dep,
       sdbusplus,
   ],
   install: true,
@@ -160,7 +156,7 @@
 deps = [
   libpldm_dep,
   libpldmutils,
-  nlohmann_json,
+  nlohmann_json_dep,
   phosphor_dbus_interfaces,
   phosphor_logging_dep,
   sdbusplus,