meta-aspeed: ast2600: require rather than include the arch

We should `require` the include file for the architecture settings
rather than `include` them so that bitbake errors out if they are not
found.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I3c74909251846afce240dfe88dc777493b596c30
diff --git a/meta-aspeed/conf/machine/include/ast2600.inc b/meta-aspeed/conf/machine/include/ast2600.inc
index 1e5e1f8..dafb0cd 100644
--- a/meta-aspeed/conf/machine/include/ast2600.inc
+++ b/meta-aspeed/conf/machine/include/ast2600.inc
@@ -6,4 +6,4 @@
 
 include conf/machine/include/soc-family.inc
 require conf/machine/include/aspeed.inc
-include conf/machine/include/arm/arch-armv7a.inc
+require conf/machine/include/arm/arch-armv7a.inc