Azure: Rework our Rockchip jobs slightly

Currently the 64bit "rk" job is close to and sometimes goes over the job
time limit.  Let us rework this in to one job for "rk" and "rv" (which
are the SoC prefixes) jobs which include or exclude "rockchip" the board
vendor.  This gives us two jobs of similar numbers of platforms to build
now instead.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>