cmos_get_fd_drive_type() is declared in "hw/block/fdc.h".
This currently works because "hw/i386/pc.h" happens to
include it. Simplify including the correct header.

Fixes: 2055dbc1 ("acpi: move aml builder code for floppy device")
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-Id: <20200724084315.1606-1-f4bug@amsat.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>