gdb-cross-canadian: Depend on nativesdk-python3-importlib

Add missing dependency on nativesdk-python3-importlib so the imp Python
module is installed.

Before this patch, running gdb from the sdk would give the following
error:

Python Exception <class 'ImportError'> No module named 'imp':

(From OE-Core rev: ad00a31fbe93e073a2d83616efcd08c5a7ef37c9)

Signed-off-by: George McCollister <george.mccollister@gmail.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/gdb/gdb-cross-canadian.inc

@@ -14,7 +14,8 @@ GDBPROPREFIX = "--program-prefix='${TARGET_PREFIX}'"
 PACKAGECONFIG ??= "python readline"
 PACKAGECONFIG[python] = "--with-python=${WORKDIR}/python,--without-python,nativesdk-python3, \
                          nativesdk-python3-core nativesdk-python3-lang nativesdk-python3-re \
-                         nativesdk-python3-codecs nativesdk-python3-netclient"
+                         nativesdk-python3-codecs nativesdk-python3-netclient \
+                         nativesdk-python3-importlib"
 PACKAGECONFIG[readline] = "--with-system-readline,--without-system-readline,nativesdk-readline"
 
 SSTATE_DUPWHITELIST += "${STAGING_DATADIR}/gdb"