clover: Add constructor for image_rd_argument.

Fix defect reported by Coverity Scan.

Uninitialized pointer field (UNINIT_CTOR)
member_not_init_in_gen_ctor: The compiler-generated constructor for this class does not initialize st.

Signed-off-by: Vinson Lee <vlee@freedesktop.org>
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13500>

src/gallium/frontends/clover/core/kernel.cpp

@@ -584,6 +584,9 @@ kernel::constant_argument::unbind(exec_context &ctx) {
       buf->resource_in(*ctx.q).unbind_surface(*ctx.q, st);
 }
 
+kernel::image_rd_argument::image_rd_argument() : st(nullptr) {
+}
+
 void
 kernel::image_rd_argument::set(size_t size, const void *value) {
    if (!value)

src/gallium/frontends/clover/core/kernel.hpp

@@ -218,6 +218,8 @@ namespace clover {
 
       class image_rd_argument : public image_argument {
       public:
+         image_rd_argument();
+
          virtual void set(size_t size, const void *value);
          virtual void bind(exec_context &ctx,
                            const binary::argument &barg);