cpu/via/c7: Don't manually include udelay_io.c

Use UDELAY_IO selected by CPU_VIA_C7, so no manual inclusion
(or secondary UDELAY implementation) is needed

Change-Id: Ib086a1bfe8ffca5757bf553c5a62a45da7a410b6
Signed-off-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-on: https://review.coreboot.org/13782
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

src/cpu/via/c7/Kconfig

@@ -9,7 +9,9 @@ config CPU_SPECIFIC_OPTIONS
 	select ARCH_VERSTAGE_X86_32
 	select ARCH_ROMSTAGE_X86_32
 	select ARCH_RAMSTAGE_X86_32
-	select UDELAY_TSC
+	# Missing tsc_freq_mhz and TSC_CONSTANT_RATE
+	#select UDELAY_TSC
+	select UDELAY_IO
 	select MMX
 	select SSE2