sandbox: eth: Add a function to skip ping timeouts

When called, the next call to receive will trigger a 10-second leap
forward in time to avoid waiting for time to pass when tests are
evaluating timeout behavior.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/sandbox/include/asm/eth.h b/arch/sandbox/include/asm/eth.h
index 4b79ede..88804fb 100644
--- a/arch/sandbox/include/asm/eth.h
+++ b/arch/sandbox/include/asm/eth.h
@@ -12,4 +12,6 @@
 
 void sandbox_eth_disable_response(int index, bool disable);
 
+void sandbox_eth_skip_timeout(void);
+
 #endif /* __ETH_H */