accel: ethosu: Fix NPU_OP_ELEMENTWISE validation with scalar

accel: ethosu: Fix NPU_OP_ELEMENTWISE validation with scalar

The NPU_OP_ELEMENTWISE instruction uses a scalar value for IFM2 if the
IFM2_BROADCAST "scalar" mode is set. It is a bit (7) on the u65 and
part of a field (bits 3:0) on the u85. The driver was hardcoded to the
u85.

Fixes: 5a5e9c0228e6 ("accel: Add Arm Ethos-U NPU driver")
Reviewed-and-Tested-by: Anders Roxell <anders.roxell@linaro.org>
Link: https://patch.msgid.link/20260218-ethos-fixes-v1-2-be3fa3ea9a30@kernel.org
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>