hppa: remove the empty hppa_sys.h file

hppa: remove the empty hppa_sys.h file

This file is now just a simple wrapper that includes hppa_hardware.h so remove
the file completely, and update its single user in machine.c to include
hppa_hardware.h directly.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Helge Deller <deller@gmx.de>
Message-Id: <20220504092600.10048-48-mark.cave-ayland@ilande.co.uk>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>