[PATCH] ALSA: cs4236: fix return check from call to pnp_port_start

[Colin King <colin.king@canonical.com>]

From: Colin Ian King <colin.king@canonical.com>

Currently the return from pnp_port_start is being checked for validity
by checking if it is greater or equal to zero, however, the return
is unsigned and hence this check is always true.  An 0 return from
pnp_port_start is actually an error, so fix the check by checking
for validity when it is non-zero.

Detected by CoverityScan, CID#1468334 ("Unsigned compared to 0")

Fixes: a9824c868a2c ("[ALSA] Add CS4232 PnP BIOS support")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 sound/isa/cs423x/cs4236.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/isa/cs423x/cs4236.c b/sound/isa/cs423x/cs4236.c
index 70559e59d18f..2211c39d2c18 100644
--- a/sound/isa/cs423x/cs4236.c
+++ b/sound/isa/cs423x/cs4236.c
@@ -292,7 +292,7 @@ static int snd_cs423x_pnp_init_mpu(int dev, struct pnp_dev *pdev)
 		mpu_irq[dev] = SNDRV_AUTO_IRQ;
 	} else {
 		mpu_port[dev] = pnp_port_start(pdev, 0);
-		if (mpu_irq[dev] >= 0 &&
+		if (!mpu_irq[dev] &&
 		    pnp_irq_valid(pdev, 0) && pnp_irq(pdev, 0) >= 0) {
 			mpu_irq[dev] = pnp_irq(pdev, 0);
 		} else {
-- 
2.17.1