ir3: add pointer from ir3_shader_variant to ir3_shader

Needed in the next commit to get the shader key for a variant.

Signed-off-by: Job Noorman <jnoorman@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33602>

src/freedreno/ir3/ir3_shader.c

@@ -510,6 +510,7 @@ alloc_variant(struct ir3_shader *shader, const struct ir3_shader_key *key,
       return NULL;
 
    v->id = ++shader->variant_count;
+   v->shader = shader;
    v->shader_id = shader->id;
    v->binning_pass = !!nonbinning;
    v->nonbinning = nonbinning;

src/freedreno/ir3/ir3_shader.h

@@ -633,6 +633,7 @@ struct ir3_shader_variant {
 
    /* id of the shader the variant came from (for debug) */
    uint32_t shader_id;
+   struct ir3_shader *shader;
 
    struct ir3_shader_key key;