panfrost: factor out meat of pan_bytes_per_pixel_tib to helper

We're going to have to do this from non arch-specific code, so let's
factor the meat out into a helper so we don't need to repeat the logic.

Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38968>

src/panfrost/lib/pan_desc.c

@@ -455,17 +455,7 @@ pan_bytes_per_pixel_tib(enum pipe_format format)
 {
    const struct pan_blendable_format *bf =
       GENX(pan_blendable_format_from_pipe_format)(format);
-
-   if (bf->internal) {
-      /* Blendable formats are always 32-bits in the tile buffer,
-       * extra bits are used as padding or to dither */
-      return 4;
-   } else {
-      /* Non-blendable formats are raw, rounded up to the nearest
-       * power-of-two size */
-      unsigned bytes = util_format_get_blocksize(format);
-      return util_next_power_of_two(bytes);
-   }
+   return pan_format_tib_size(format, bf->internal);
 }
 
 static unsigned

src/panfrost/lib/pan_format.h

@@ -129,6 +129,21 @@ pan_format_get_plane_blocksize(enum pipe_format format, unsigned plane_idx)
    }
 }
 
+static inline unsigned
+pan_format_tib_size(enum pipe_format format, bool internal)
+{
+   if (internal) {
+      /* Blendable formats are always 32-bits in the tile buffer,
+       * extra bits are used as padding or to dither */
+      return 4;
+   } else {
+      /* Non-blendable formats are raw, rounded up to the nearest
+       * power-of-two size */
+      unsigned bytes = util_format_get_blocksize(format);
+      return util_next_power_of_two(bytes);
+   }
+}
+
 typedef uint32_t mali_pixel_format;
 
 /* pan bind flags */