soc: ti: k3-ringacc: fix: warn: variable dereferenced before check 'ring'

Fix build warning in k3_ringacc_ring_cfg():

smatch warnings:
drivers/soc/ti/k3-ringacc.c:562 k3_ringacc_ring_cfg() warn: variable dereferenced before check 'ring' (see line 559)

  557  int k3_ringacc_ring_cfg(struct k3_ring *ring, struct k3_ring_cfg *cfg)
  558  {
 @559           struct k3_ringacc *ringacc = ring->parent;
                                             ^^^^^^^^^^^^
Dereference.

  560           int ret = 0;
  561
 @562           if (!ring || !cfg)
                    ^^^^

Check too late.  Delete it?

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>