build(fix): pass arch to finch-core install.dependencies target (runfinch#1034)

Issue #, if available:

*Description of changes:*
Fixes cross-building after this finch-core change
(runfinch/finch-core#370) is merged and
submodules are synced

*Testing done:*



- [x] I've reviewed the guidance in CONTRIBUTING.md


#### License Acceptance

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license.

Signed-off-by: Justin Alvarez <[email protected]>

Author: pendo324

Diff for: Makefile

@@ -64,7 +64,7 @@ all: arch-test finch install.finch-core-dependencies finch.yaml networks.yaml co
 
 .PHONY: install.finch-core-dependencies
 install.finch-core-dependencies:
-	OUTDIR=$(OUTDIR) "$(MAKE)" -C $(FINCH_CORE_DIR) install.dependencies
+	OUTDIR=$(OUTDIR) ARCH=$(ARCH) "$(MAKE)" -C $(FINCH_CORE_DIR) install.dependencies
 
 .PHONY: finch.yaml
 finch.yaml: $(OS_OUTDIR)/finch.yaml