net: phy: realtek: rename RTL821x_INER_INIT to RTL8211B_INER_INIT

This macro is only used by the RTL8211B code. RTL8211E and RTL8211F both
use other bits to initialize the RTL821x_INER register.
No functional changes.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>