Add FWSPICS1 and SPI1CS1 in AST2500 pinctrl group.
On AST2500 EVB, FWSPICS1 can be supported by default.
An extra jumper, J45, should be configured before
enabling SPI1CS1.
Signed-off-by: Chin-Ting Kuo <chin-ting_kuo@aspeedtech.com> Reviewed-by: Cédric Le Goater <clg@kaod.org>