env: Rename eth_getenv_enetaddr() to eth_env_get_enetaddr()

Rename this function for consistency with env_get().

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/board/renesas/silk/silk.c b/board/renesas/silk/silk.c
index e13a38f..a8de402 100644
--- a/board/renesas/silk/silk.c
+++ b/board/renesas/silk/silk.c
@@ -135,7 +135,7 @@
 	unsigned char enetaddr[6];
 
 	ret = sh_eth_initialize(bis);
-	if (!eth_getenv_enetaddr("ethaddr", enetaddr))
+	if (!eth_env_get_enetaddr("ethaddr", enetaddr))
 		return ret;
 
 	/* Set Mac address */