isl: Remove isl_format_layout::bpb

struct isl_format_layout contained two near-redundant members: bpb (bits
per block) and bs (block size). There do exist some hardware formats for
which bpb != 8 * bs, but Vulkan does not use them. Therefore we don't
need bpb.

src/isl/isl.h

@@ -643,7 +643,6 @@ struct isl_channel_layout {
 struct isl_format_layout {
    enum isl_format format;
 
-   uint16_t bpb; /**< Bits per block */
    uint8_t bs; /**< Block size, in bytes, rounded towards 0 */
    uint8_t bw; /**< Block width, in pixels */
    uint8_t bh; /**< Block height, in pixels */

src/isl/isl_format_layout_gen.bash

@@ -99,7 +99,7 @@ do
     cat <<EOF
    [$format] = {
       $format,
-      .bs = $((bpb/8)), .bpb = $bpb,
+      .bs = $((bpb/8)),
       .bw = $bw, .bh = $bh, .bd = $bd,
       .channels = {
           .r = { $red },