sysutils/cpu-x: try to further improve the port (part one)

• Setting PKGNAMESUFFIX=-${FLAVOR} for all flavors was actually misleading: graphic version (GTK+) includes ncurses UI as well, so mark the console-only one as such (`tuionly') while keeping the full package unsuffixed
• Assembler is only used to translate two x86 files which belong to the memory bandwidth code, make it conditional based on the ${ARCH} and thus (hopefully) unbreak the build on !x86

PR: 251785
(cherry picked from commit ca9e112b42fdc623acc09e7ec5707249e08fa6ad)