defconfig: move qcs405 defconfigs to vendor/ subdirectory

Move qcs405 defconfigs down one level to vendor/. Create
symlinks as necessary for userspace components that are
still hard-coded to the older location.

Change-Id: Iffe729b76a2c401fc4bc899cfcaff91decde2211
Signed-off-by: Kaushal Kumar <kaushalk@codeaurora.org>