alpha: Switch to GENERIC_CLOCKEVENTS

This allows us to get rid of some hacky code for SMP.  Get rid of
some cycle counter hackery that's now handled by generic code via
clocksource + clock_event_device objects.

Signed-off-by: Richard Henderson <rth@twiddle.net>

arch/alpha/Kconfig

@@ -16,6 +16,7 @@ config ALPHA
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
+	select GENERIC_CLOCKEVENTS
 	select GENERIC_SMP_IDLE_THREAD
 	select GENERIC_STRNCPY_FROM_USER
 	select GENERIC_STRNLEN_USER