linux-user: add pseudo /proc/hardware for m68k

linux-user: add pseudo /proc/hardware for m68k

Debian console-setup uses /proc/hardware to guess the keyboard layout.
If the file /proc/hardware cannot be opened, the installation fails.

This patch adds a pseudo /proc/hardware file to report the model of
the machine. Instead of reporting a known and fake model, it
reports "qemu-m68k", which is true, and avoids to set the configuration
for an Amiga/Apple/Atari and let the user to chose the good one.

Bug: https://github.com/vivier/qemu-m68k/issues/34
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190517133149.19593-3-laurent@vivier.eu>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>