selftests: drv-net: fix RPS mask handling in toeplitz test

The toeplitz.py test passed the hex mask without "0x" prefix (e.g.,
"300" for CPUs 8,9). The toeplitz.c strtoul() call wrongly parsed this
as decimal 300 (0x12c) instead of hex 0x300.

Pass the prefixed mask to toeplitz.c, and the unprefixed one to sysfs.

Fixes: 9cf9aa7 ("selftests: drv-net: hw: convert the Toeplitz test to Python")
Reviewed-by: Nimrod Oren <noren@nvidia.com>
Signed-off-by: Gal Pressman <gal@nvidia.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20260112173715.384843-2-gal@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: gal-pressman

tools/testing/selftests/drivers/net/hw/toeplitz.py

@@ -94,12 +94,14 @@ def _configure_rps(cfg, rps_cpus):
     mask = 0
     for cpu in rps_cpus:
         mask |= (1 << cpu)
-    mask = hex(mask)[2:]
+
+    mask = hex(mask)
 
     # Set RPS bitmap for all rx queues
     for rps_file in glob.glob(f"/sys/class/net/{cfg.ifname}/queues/rx-*/rps_cpus"):
         with open(rps_file, "w", encoding="utf-8") as fp:
-            fp.write(mask)
+            # sysfs expects hex without '0x' prefix, toeplitz.c needs the prefix
+            fp.write(mask[2:])
 
     return mask