Fix typo for Mtdev pkgconfig target

Change-Id: Id6e7057e8010f67ba1c8ce948abc59bc7abf7b7b
Reviewed-by: Qt CMake Build Bot
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

cmake/FindMtdev.cmake

@@ -2,6 +2,6 @@ find_package(PkgConfig)
 
 pkg_check_modules(Mtdev mtdev IMPORTED_TARGET)
 
-if (NOT TARGET PkgConfig::MtDev)
+if (NOT TARGET PkgConfig::Mtdev)
     set(Mtdev_FOUND 0)
 endif()