spl: Kconfig: Rename SPL_USBETH_SUPPORT to SPL_USB_ETHER to match with the U-boot CONFIG

Rename CONFIG_SPL_USBETH_SUPPORT to CONFIG_SPL_USB_ETHER.

This enables users to block text using CONFIG_IS_ENABLED() instead
of resorting to #if ladders with SPL and non-SPL cases.

Signed-off-by: Faiz Abbas <faiz_abbas@ti.com>
diff --git a/include/configs/bav335x.h b/include/configs/bav335x.h
index 48cd285..e7f65d6 100644
--- a/include/configs/bav335x.h
+++ b/include/configs/bav335x.h
@@ -395,7 +395,7 @@
 #define CONFIG_AM335X_USB1
 #define CONFIG_AM335X_USB1_MODE MUSB_HOST
 
-#if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_USBETH_SUPPORT)
+#if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_USB_ETHER)
 /* disable host part of MUSB in SPL */
 /* disable EFI partitions and partition UUID support */
 #endif