linux patches to fix kernel oops at spi-tty close (e.g. reboot or killall ash)

Signed-off-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>
linux CONFIG_SPI_TTY_PLAIN=m: compile spi-tty-plain driver as a module

This is needed in order to permit run-avrdude rmmod spi-tty-plain driver.

Signed-off-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>
bathos-mcuio.hex: removed 'data_ready_handle to' log message

bathos-mcuio commit f9577603c
This log message is useful for debug only, so it must not be compiled in the
linino_distro.

Signed-off-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>