hw/display: Use the IEC binary prefix definitions

hw/display: Use the IEC binary prefix definitions

It eases code review, unit is explicit.

Patch generated using:

  $ git grep -E '(1024|2048|4096|8192|(<<|>>).?(10|20|30))' hw/ include/hw/

and modified manually.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20180625124238.25339-15-f4bug@amsat.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>