global: Migrate CONFIG_I2C_MULTI_BUS to CFG

Perform a simple rename of CONFIG_I2C_MULTI_BUS to CFG_I2C_MULTI_BUS

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/README b/README
index 8408676..0561835 100644
--- a/README
+++ b/README
@@ -955,7 +955,7 @@
 		You should define these to the GPIO value as given directly to
 		the generic GPIO functions.
 
-		CONFIG_I2C_MULTI_BUS
+		CFG_I2C_MULTI_BUS
 
 		This option allows the use of multiple I2C buses, each of which
 		must have a controller.	 At any point in time, only one bus is