agx: Remove unused allocation

Relic from early RA attempts.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24635>

src/asahi/compiler/agx_register_allocate.c

@@ -1101,8 +1101,6 @@ agx_insert_parallel_copies(agx_context *ctx, agx_block *block)
 void
 agx_ra(agx_context *ctx)
 {
-   unsigned *alloc = calloc(ctx->alloc, sizeof(unsigned));
-
    agx_compute_liveness(ctx);
    uint8_t *ncomps = calloc(ctx->alloc, sizeof(uint8_t));
    agx_instr **src_to_collect_phi = calloc(ctx->alloc, sizeof(agx_instr *));
@@ -1272,5 +1270,4 @@ agx_ra(agx_context *ctx)
    free(ncomps);
    free(sizes);
    free(visited);
-   free(alloc);
 }