python3: fix multilib qa issue

Enable tk in PACKAGECONFIG as below in conf/local.conf.
PACKAGECONFIG_append_pn-python3 = " tk"
 $ bitbake lib32-python3
   ERROR: lib32-python3-3.9.6-r0 do_package_qa: QA Issue: /usr/lib/python3.9/lib-dynload/_tkinter.cpython-39-i386-linux-gnu.so contained in package lib32-python3-tkinter requires libtk8.6.so, but no providers found in RDEPENDS_lib32-python3-tkinter? [file-rdeps]
   ERROR: lib32-python3-3.9.6-r0 do_package_qa: QA run found fatal errors. Please consider fixing them.

So add MLPREFIX prefix to fix the above issue.

(From OE-Core rev: 4a839d7c66e4589050ce3f145a8c7cf820e6b35d)

Signed-off-by: Mingli Yu <mingli.yu@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/python/python3_3.9.6.bb

@@ -374,8 +374,8 @@ RDEPENDS:libpython3:append:libc-glibc = " libgcc"
 RDEPENDS:${PN}-ctypes:append:libc-glibc = " ${MLPREFIX}ldconfig"
 RDEPENDS:${PN}-ptest = "${PN}-modules ${PN}-tests ${PN}-dev unzip bzip2 libgcc tzdata-europe coreutils sed"
 RDEPENDS:${PN}-ptest:append:libc-glibc = " locale-base-tr-tr.iso-8859-9"
-RDEPENDS:${PN}-tkinter += "${@bb.utils.contains('PACKAGECONFIG', 'tk', 'tk tk-lib', '', d)}"
-RDEPENDS:${PN}-idle += "${@bb.utils.contains('PACKAGECONFIG', 'tk', '${PN}-tkinter tcl', '', d)}"
+RDEPENDS:${PN}-tkinter += "${@bb.utils.contains('PACKAGECONFIG', 'tk', '${MLPREFIX}tk ${MLPREFIX}tk-lib', '', d)}"
+RDEPENDS:${PN}-idle += "${@bb.utils.contains('PACKAGECONFIG', 'tk', '${PN}-tkinter ${MLPREFIX}tcl', '', d)}"
 RDEPENDS:${PN}-dev = ""
 RDEPENDS:${PN}-pydoc += "${PN}-io"