arm: zynq defconfig: Remove input event debugging

In the general Zynq defconfig input device event debugging
is enabled, which fills the log buffer with evbug messages
when using a keyboard or mouse. These messages aren't useful
unless actively debugging input devices and can obscure
more relevant log messages, so disable them by default.

Signed-off-by: Rob Armstrong <ra@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>