northbridge/intel/i440bx: Unify UDELAY selection

Instead of manually including udelay_io.c in each romstage,
select UDELAY_IO for all i440BX boards in the chipset.

Change-Id: I411191927f3fba1d0749edcf79378e8013fb195a
Signed-off-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-on: https://review.coreboot.org/13781
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

src/cpu/intel/socket_PGA370/Kconfig

@@ -17,7 +17,6 @@ config CPU_INTEL_SOCKET_PGA370
 	bool
 	select CPU_INTEL_MODEL_6XX
 	select MMX
-	select UDELAY_TSC
 
 if CPU_INTEL_SOCKET_PGA370