Enable XPU int matmul (#1547)

Signed-off-by: jiqing-feng <[email protected]>

Author: jiqing-feng

bitsandbytes/backends/cpu_xpu_common.py

@@ -194,8 +194,10 @@ def int8_linear_matmul_impl(
 
     A_reshaped = A.reshape(m, k)
 
-    # torch._int_mm is available on CPU since torch 2.4
-    if _torch_version_prereq(2, 4) and A.device.type == "cpu":
+    # torch._int_mm is available on CPU since torch 2.4, XPU since torch 2.6
+    if (A.device.type == "cpu" and _torch_version_prereq(2, 4)) or (
+        A.device.type == "xpu" and _torch_version_prereq(2, 6)
+    ):
         C = torch._int_mm(A_reshaped, B.T).to(dtype)
     else:
         C = torch.matmul(A_reshaped.float(), B.t().float()).to(dtype)