net: phy/realtek: Add support for RTL8211DN and RTL8211E phy modules

This patch adds support for Realtek PHY modules RTL8211DN and
RTL8211E (variants: RTL8211E-VB-CG, RTL8211E-VL-CG, RTL8211EG-VB-CG),
which can be found on Freescale's T1040RDB boards.

To make the driver more generic across 8211 family, a generic name 8211x
is added for macros and function names.

Signed-off-by: Bhupesh Sharma <bhupesh.sharma@freescale.com>
Acked-by: York Sun <yorksun@freescale.com>