LF-3715-1 net: phy: realtek: change "rtl821x,clkout_en" to "rtl821x,clkout-disable"

LF-3715-1 net: phy: realtek: change "rtl821x,clkout_en" to "rtl821x,clkout-disable"

For PHY RTL8211FDI-CG, CLKOUT clock default is enabled by hardware, use
"rtl821x,clkout-disable" property to disable CLKOUT if user required. If
use "rtl821x,clkout_en" property to enable CLKOUT clock, it will block existing
cases which need this CLKOUT for MAC but doesn't add this property. It's
safe to change "rtl821x,clkout_en" to "rtl821x,clkout-disable", as to be
removed property("rtl821x,clkout_en") never been used in the kernel
tree.

Camelia Groza validated on LS1043ARDB.

Tested-by: Camelia Groza <camelia.groza@nxp.com>
Reviewed-by: Camelia Groza <camelia.groza@nxp.com>
Reviewed-by: Jun Li <jun.li@nxp.com>
Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Acked-by: Jason Liu <jason.hui.liu@nxp.com>