sycl: decline float -> PTQ1_0/PQ2_0 copies instead of asserting

Adding the two types to ggml_sycl_is_quantized_type() made supports_op
accept f32/f16/bf16 -> PTQ1_0/PQ2_0 copies, but there is no quantize-rows
kernel for either, so ggml_sycl_cpy() took the float -> quantized branch
and died on GGML_ASSERT(ggml_sycl_can_quantize_rows_sycl(...)) at
cpy.cpp:1298/1302/1308.

Neither format can be produced by a row-at-a-time GPU kernel: the packing
assumes the Hadamard rotation the offline converter applies, so the right
answer is to decline the pair and let the scheduler place it elsewhere,
not to add a kernel. Quantized -> same-quantized copies are unaffected and
still take the memcpy path.

Reported by @dwymark on an Arc B390 (Panther Lake Xe3); reproduced on an
Arc Pro B50.

  test -b SYCL0 -o CPY -p "ptq1_0|pq2_0"
    before: abort at cpy.cpp:1298
    after:  18/18 tests passed, float -> ternary reports "not supported"

No regression: MUL_MAT 204/204, MUL_MAT_ID 150/150, GET_ROWS 8/8 for the
two types.

The unrelated tq2_0 -> tq2_0 abort at cpy.cpp:1455 and the SET_ROWS abort
at set_rows.cpp:549 are both present on prism and untouched here.

Author: kiljoy001

ggml/src/ggml-sycl/ggml-sycl.cpp

@@ -6146,6 +6146,16 @@ static bool do_ggml_backend_sycl_device_supports_op(ggml_backend_dev_t dev, cons
                 ggml_type src0_type = op->src[0]->type;
                 ggml_type src1_type = op->src[1]->type;
 
+                // Quantizing a float row into PTQ1_0 or PQ2_0 has no kernel: both are
+                // produced offline by the converter, which also applies the Hadamard
+                // rotation the packing assumes. ggml_sycl_cpy() would take the
+                // float -> quantized branch and assert, so decline the pair here and let
+                // the scheduler fall back. The quant -> same-quant copies are handled.
+                if ((src1_type == GGML_TYPE_PTQ1_0 || src1_type == GGML_TYPE_PQ2_0) &&
+                    src0_type != src1_type) {
+                    return false;
+                }
+
                 if (src0_type == GGML_TYPE_F16) {
                     if (src1_type == GGML_TYPE_Q2_K ||
                         src1_type == GGML_TYPE_Q3_K ||