qemu-options.hx: use KiB, MiB, GiB for power-of-2 units

Use MiB &Co instead of MB &Co when the talk is about
power-of-two-based sizes, in qemu-options.hx.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3222
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
1 file changed