arm64: zynqmp: remove Avnet UltraZed-EV Starter Kit

arm64: zynqmp: remove Avnet UltraZed-EV Starter Kit

Nobody seems interested and able to keep this board supported, and
xilinx_zynqmp_virt_defconfig is supposed to be enough for any zynqmp board.

See the discussion at: https://lore.kernel.org/u-boot/CAPnjgZ3hHbyiFf=_Lp-Wz_XOWBkV-3vK4Q3xp=7bcERw-spNpA@mail.gmail.com/T/#m76d726f1ab3f7074c8105c9a2af2110ac7d18708

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Link: https://lore.kernel.org/r/20230111082554.1930782-1-luca.ceresoli@bootlin.com
Signed-off-by: Michal Simek <michal.simek@amd.com>