riscv: Add missing sentinel in ocores_i2c.c

The ocores_i2c.c driver is missing a sentinel at the end of
the compatible strings list.  This causes the "dm compat" command
to spew garbage.

Signed-off-by: Thomas Skibo <thomas-git@skibo.net>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
diff --git a/drivers/i2c/ocores_i2c.c b/drivers/i2c/ocores_i2c.c
index 088ba9a..f129ec3 100644
--- a/drivers/i2c/ocores_i2c.c
+++ b/drivers/i2c/ocores_i2c.c
@@ -626,6 +626,7 @@
 { .compatible = "aeroflexgaisler,i2cmst", .data = TYPE_GRLIB },
 { .compatible = "sifive,fu540-c000-i2c" },
 { .compatible = "sifive,i2c0" },
+{ }
 };
 
 U_BOOT_DRIVER(i2c_ocores) = {