iris: Drop redundant iris_address::write flag.

The write flag is redundant since it can be inferred easily from the
iris_address::access domain.  This allows the iris_address struct to
be laid out more efficiently in memory, leading to a measurable
improvement in several Piglit Drawoverhead test-cases.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3875>

src/gallium/drivers/iris/iris_genx_macros.h

@@ -52,7 +52,8 @@ __gen_combine_address(struct iris_batch *batch, void *location,
    uint64_t result = addr.offset + delta;
 
    if (addr.bo) {
-      iris_use_pinned_bo(batch, addr.bo, addr.write, addr.access);
+      iris_use_pinned_bo(batch, addr.bo,
+                         !iris_domain_is_read_only(addr.access), addr.access);
       /* Assume this is a general address, not relative to a base. */
       result += addr.bo->gtt_offset;
    }
@@ -129,5 +130,5 @@ UNUSED static struct iris_address
 rw_bo(struct iris_bo *bo, uint64_t offset, enum iris_domain access)
 {
    return (struct iris_address) { .bo = bo, .offset = offset,
-                                  .write = true, .access = access };
+                                  .access = access };
 }

src/gallium/drivers/iris/iris_query.c

@@ -101,7 +101,6 @@ query_mem64(struct iris_query *q, uint32_t offset)
    struct iris_address addr = {
       .bo = iris_resource_bo(q->query_state_ref.res),
       .offset = q->query_state_ref.offset + offset,
-      .write = true,
       .access = IRIS_DOMAIN_OTHER_WRITE
    };
    return gen_mi_mem64(addr);

src/gallium/drivers/iris/iris_screen.h

@@ -137,10 +137,9 @@ struct iris_vtable {
 };
 
 struct iris_address {
-   enum iris_domain access;
    struct iris_bo *bo;
    uint64_t offset;
-   bool write;
+   enum iris_domain access;
 };
 
 struct iris_screen {