'struct knav_range_ops' is not modified in these drivers.

Constifying this structure moves some data to a read-only section, so
increase overall security.

On a x86_64, with allmodconfig:
Before:
======
   text	   data	    bss	    dec	    hex	filename
   7498	   1193	      0	   8691	   21f3	drivers/soc/ti/knav_qmss_acc.o

After:
=====
   text	   data	    bss	    dec	    hex	filename
   7566	   1145	      0	   8711	   2207	drivers/soc/ti/knav_qmss_acc.o
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/a8b4b428f97fc584f38bf45100aa9da241aeb935.1719159074.git.christophe.jaillet@wanadoo.frSigned-off-by: Nishanth Menon <nm@ti.com>