CONFIG_PC is left-over cruft after the introduction of CONFIG_X86_PC with
the subarch split.  Remove it, and fixup the remaining users to depend on
CONFIG_X86_PC instead.
Signed-off-by: NArthur Othieno <a.othieno@bluewin.ch>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>