Copter: landing detector checks baro climb rate

Barometer climb rate must be -150cm/s ~ +150cm/s
This threshold is generous because we already use the inertial
navigation climb rate so this is just to catch cases where inertial nav
is very incorrect in it's climbrate estimates
DataFlash: log baro climbrate
platforms: Basic Zynq Linux platform support

Select the Xilinx arm cross compilers and stubbed sensor suite.

CLI loop runs fine under emulation.
zynq port: copy PRU RC IO to zynq, will edit later
zynq port - quick hack to add zynq rcinput/output functions

Signed-off-by: John Williams <john@whelanwilliams.net>
PRU: Move TICK #defines local to cpp file.

When adding the Zynq RcOutput driver we use similar definitions so this
wil lavoid macro redefinition errors/warnings

Signed-off-by: John Williams <john@whelanwilliams.net>
zynq: it works!

pulse train input working ok

Signed-off-by: John Williams <john@whelanwilliams.net>
zynq: add HIL build target for zynq

Signed-off-by: John Williams <john@whelanwilliams.net>
zynq: working RCInput and RCOutput for Zynq

Signed-off-by: John Williams <john@whelanwilliams.net>
zynq: hack in HIL support for zynq build

Signed-off-by: John Williams <john@whelanwilliams.net>