ice: ice_base.c: Add const modifier to params and vars

Add const modifier to function parameters and variables where appropriate
in ice_base.c and corresponding declarations in ice_base.h.

The reason for starting the change is that read-only pointers should be
marked as const when possible to allow for smoother and more optimal code
generation and optimization as well as allowing the compiler to warn the
developer about potentially unwanted modifications, while not carrying
noticeable negative impact.

Reviewed-by: Andrii Staikov <andrii.staikov@intel.com>
Reviewed-by: Sachin Bahadur <sachin.bahadur@intel.com>
Signed-off-by: Jan Glaza <jan.glaza@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>