std.Target: bump feature bit count from 288 to 317

    /lib/std/debug.zig:559:14: error: reached unreachable code
        if (!ok) unreachable; // assertion failure
                 ^~~~~~~~~~~
    /lib/std/Target/riscv.zig:335:21: note: called at comptime here
        std.debug.assert(len <= CpuFeature.Set.needed_bit_count);
        ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Author: alexrp

lib/std/Target.zig

@@ -1195,7 +1195,7 @@ pub const Cpu = struct {
         pub const Set = struct {
             ints: [usize_count]usize,
 
-            pub const needed_bit_count = 288;
+            pub const needed_bit_count = 317;
             pub const byte_count = (needed_bit_count + 7) / 8;
             pub const usize_count = (byte_count + (@sizeOf(usize) - 1)) / @sizeOf(usize);
             pub const Index = std.math.Log2Int(std.meta.Int(.unsigned, usize_count * @bitSizeOf(usize)));