anv: fix FS output <-> attachment map building

The arrays is first memset to OUTPUT_DISABLED, but if we iterate over
MAX_RTS instead of the actual attachment count, we end up resetting any
values not set by the application to the, probably identity, that comes
from the state.

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/37531>

src/intel/vulkan/genX_cmd_draw.c

@@ -665,7 +665,7 @@ cmd_buffer_maybe_flush_rt_writes(struct anv_cmd_buffer *cmd_buffer,
    /* Build a map of fragment color output to attachment */
    uint8_t rt_to_att[MAX_RTS];
    memset(rt_to_att, ANV_COLOR_OUTPUT_DISABLED, MAX_RTS);
-   for (uint32_t i = 0; i < MAX_RTS; i++) {
+   for (uint32_t i = 0; i < gfx->color_att_count; i++) {
       if (dyn->cal.color_map[i] != MESA_VK_ATTACHMENT_UNUSED)
          rt_to_att[dyn->cal.color_map[i]] = i;
    }