layers.txt: bump meta-smartphone a bit

Signed-off-by: Simon Busch <morphis@gravedo.de>
Update to use tmp-glibc instead of tmp-eglibc

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Set BRANCH_COMMON correctly to testing

Signed-off-by: Simon Busch <morphis@gravedo.de>