fpga: altera-fpga2sdram: remove unused struct 'prop_map'

'prop_map' has been unused since the original
commit e5f8efa5 ("ARM: socfpga: fpga bridge driver support").

Remove it.
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: Russ Weight <russ.weight@linux.dev>
Acked-by: Xu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/20240530205245.125513-1-linux@treblig.orgSigned-off-by: Xu Yilun <yilun.xu@linux.intel.com>

drivers/fpga/altera-fpga2sdram.c

@@ -75,12 +75,6 @@ static int alt_fpga2sdram_enable_set(struct fpga_bridge *bridge, bool enable)
 	return _alt_fpga2sdram_enable_set(bridge->priv, enable);
 }
 
-struct prop_map {
-	char *prop_name;
-	u32 *prop_value;
-	u32 prop_max;
-};
-
 static const struct fpga_bridge_ops altera_fpga2sdram_br_ops = {
 	.enable_set = alt_fpga2sdram_enable_set,
 	.enable_show = alt_fpga2sdram_enable_show,