[pinmux,fpv] Fix value of input_disable in mask in pinmux_assert_fpv

This feeds into the MioAttrO_A assertion, which is trying to mirror
the path "from register value to output of block". Ignoring the
pinmux_strap_sampling instance, this is done in the design by masking
by the attr_warl_o output from a prim_pad_attr instance. This instance
drives the input_disable field in the mask to 1.

Signed-off-by: Rupert Swarbrick <rswarbrick@lowrisc.org>

hw/ip/pinmux/fpv/vip/pinmux_assert_fpv.sv

@@ -296,7 +296,7 @@ module pinmux_assert_fpv
   assign mio_pad_attr_mask.keep_en = 0;
   assign mio_pad_attr_mask.schmitt_en = 0;
   assign mio_pad_attr_mask.od_en = 0;
-  assign mio_pad_attr_mask.input_disable = 0;
+  assign mio_pad_attr_mask.input_disable = 1'b1;
   assign mio_pad_attr_mask.slew_rate = '0;
   assign mio_pad_attr_mask.drive_strength[3:1] = '0;
 
@@ -323,7 +323,7 @@ module pinmux_assert_fpv
   assign dio_pad_attr_mask.keep_en     = 0;
   assign dio_pad_attr_mask.schmitt_en = 0;
   assign dio_pad_attr_mask.od_en = 0;
-  assign dio_pad_attr_mask.input_disable = 0;
+  assign dio_pad_attr_mask.input_disable = 1;
   assign dio_pad_attr_mask.slew_rate = '0;
   assign dio_pad_attr_mask.drive_strength[3:1] = '0;