python3-cffi: Add missing pkgconfig dependency

With gcc posioning fixed, this recipe showed errors, using an incorrect include
path looking at the host system. If pkgconfig is present, the correct include
paths are used. Therefore add the missing dependency.

(From OE-Core rev: 6cf0aaa3af276694709369b6007f629862e21559)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/python/python3-cffi_1.17.1.bb

@@ -8,7 +8,7 @@ SRC_URI[sha256sum] = "1c39c6016c32bc48dd54561950ebd6836e1670f2ae46128f67cf49e789
 
 SRC_URI += "file://run-ptest"
 
-inherit pypi python_setuptools_build_meta ptest
+inherit pypi python_setuptools_build_meta ptest pkgconfig
 
 do_install_ptest() {
     cp -r ${S}/testing ${D}${PTEST_PATH}