fpga: xilinx-core: add new gpio names for prog and init

Old names (prog_b and init-b) are used as a fallback for hardware
compatible with the "xlnx,fpga-slave-serial" string.

Signed-off-by: Charles Perry <charles.perry@savoirfairelinux.com>
Acked-by: Xu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/20240321220447.3260065-5-charles.perry@savoirfairelinux.com


Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com>