intel_scu_ipcutil: underflow in scu_reg_access()

intel_scu_ipcutil: underflow in scu_reg_access()

Orabug: 23330826

[ Upstream commit b1d353ad3d5835b16724653b33c05124e1b5acf1 ]

"count" is controlled by the user and it can be negative.  Let's prevent
that by making it unsigned.  You have to have CAP_SYS_RAWIO to call this
function so the bug is not as serious as it could be.

Fixes: 5369c02d951a ('intel_scu_ipc: Utility driver for intel scu ipc')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
(cherry picked from commit abd62631a46c8a27fc607ea5525d3034e8d69781)

Signed-off-by: Dan Duval <dan.duval@oracle.com>