Add links for p4-clockmod driver in x86-64 cpufreq.

AK: Made it dependent on EMBEDDED because the driver is only
useful in some special situations and should be normally not used.
Signed-off-by: "Venkatesh Pallipadi" <venkatesh.pallipadi@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>