Fix directions on how to install qemu on Gentoo
Fix directions on how to install qemu on Gentoo

In order to have ``qemu-system-x86_64`` we need to enable ``x86_64`` on ``QEMU_SOFTMMU_TARGETS``, not ``i386``
jackpot51/redox,jackpot51/redox,Stephen-Seo/redox,jackpot51/redox,redox-os/redox