crypto: caam - fix endless loop when DECO acquire fails

In case DECO0 cannot be acquired - i.e. run_descriptor_deco0() fails
with -ENODEV, caam_probe() enters an endless loop:

run_descriptor_deco0
ret -ENODEV
-> instantiate_rng
-ENODEV, overwritten by -EAGAIN
ret -EAGAIN
-> caam_probe
-EAGAIN results in endless loop

It turns out the error path in instantiate_rng() is incorrect,
the checks are done in the wrong order.

Cc: <[e-mail]> # 3.13+
Fixes: 1005bccd7a4a6 ("crypto: caam - enable instantiation of all RNG4 state handles")
Reported-by: Bryan O'Donoghue <[e-mail]>
Suggested-by: Auer Lukas <[e-mail]>
Signed-off-by: Horia Geantă <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

drivers/crypto/caam/ctrl.c

···
 		 * without any error (HW optimizations for later
 		 * CAAM eras), then try again.
 		 */
-		rdsta_val = rd_reg32(&ctrl->r4tst[0].rdsta) & RDSTA_IFMASK;
-		if ((status && status != JRSTA_SSRC_JUMP_HALT_CC) ||
-		    !(rdsta_val & (1 << sh_idx)))
-			ret = -EAGAIN;
 		if (ret)
 			break;
+
+		rdsta_val = rd_reg32(&ctrl->r4tst[0].rdsta) & RDSTA_IFMASK;
+		if ((status && status != JRSTA_SSRC_JUMP_HALT_CC) ||
+		    !(rdsta_val & (1 << sh_idx))) {
+			ret = -EAGAIN;
+			break;
+		}
+
 		dev_info(ctrldev, "Instantiated RNG4 SH%d\n", sh_idx);
 		/* Clear the contents before recreating the descriptor */
 		memset(desc, 0x00, CAAM_CMD_SZ * 7);