meson: simplify dependencies

Leverage wrapfile `[provide]` directives to simplify the dependency
searching in the meson.build.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ia5227007ba4f7e1aaa8ff1c87e53e789152cc31c
diff --git a/subprojects/stdplus.wrap b/subprojects/stdplus.wrap
index 00dae65..2f8a5f4 100644
--- a/subprojects/stdplus.wrap
+++ b/subprojects/stdplus.wrap
@@ -1,3 +1,6 @@
 [wrap-git]
-url = https://github.com/openbmc/stdplus
+url = https://github.com/openbmc/stdplus.git
 revision = HEAD
+
+[provide]
+stdplus = stdplus_dep