southbridge/amd/sb700: Set HPET min tick value to RPR recommendation

Change-Id: I766eca6369b60a79a6823bc744934e3f1fbc17b2
Signed-off-by: Timothy Pearson <tpearson@raptorengineeringinc.com>
Reviewed-on: https://review.coreboot.org/13159
Tested-by: build bot (Jenkins)
Tested-by: Raptor Engineering Automated Test Stand <noreply@raptorengineeringinc.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Martin Roth <martinroth@google.com>

src/southbridge/amd/sb700/Kconfig

@@ -50,4 +50,8 @@ config EHCI_BAR
 	hex
 	default 0xfef00000
 
+config HPET_MIN_TICKS
+	hex
+	default 0x14
+
 endif # SOUTHBRIDGE_AMD_SB700