h8/300: fix incorrect "select" directives in arch/h8300/Kconfig.cpu.

Fix the incorrect "select" directives by dropping the "CONFIG_"
prefixes, and correcting the typo "H8S2768" to "H8S2678".

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Acked-by: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>