[media] media: stb0899_drv: use time_after()

To be future-proof and for better readability the time comparisons are
modified to use time_after() instead of plain, error-prone math.
Signed-off-by: Asaf Vertz <asaf.vertz@tandemg.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/dvb-frontends/stb0899_drv.c

@@ -20,6 +20,7 @@
 */
 
 #include <linux/init.h>
+#include <linux/jiffies.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/slab.h>
@@ -691,7 +692,7 @@ static int stb0899_wait_diseqc_fifo_empty(struct stb0899_state *state, int timeo
 		reg = stb0899_read_reg(state, STB0899_DISSTATUS);
 		if (!STB0899_GETFIELD(FIFOFULL, reg))
 			break;
-		if ((jiffies - start) > timeout) {
+		if (time_after(jiffies, start + timeout)) {
 			dprintk(state->verbose, FE_ERROR, 1, "timed out !!");
 			return -ETIMEDOUT;
 		}
@@ -733,7 +734,7 @@ static int stb0899_wait_diseqc_rxidle(struct stb0899_state *state, int timeout)
 
 	while (!STB0899_GETFIELD(RXEND, reg)) {
 		reg = stb0899_read_reg(state, STB0899_DISRX_ST0);
-		if (jiffies - start > timeout) {
+		if (time_after(jiffies, start + timeout)) {
 			dprintk(state->verbose, FE_ERROR, 1, "timed out!!");
 			return -ETIMEDOUT;
 		}
@@ -782,7 +783,7 @@ static int stb0899_wait_diseqc_txidle(struct stb0899_state *state, int timeout)
 
 	while (!STB0899_GETFIELD(TXIDLE, reg)) {
 		reg = stb0899_read_reg(state, STB0899_DISSTATUS);
-		if (jiffies - start > timeout) {
+		if (time_after(jiffies, start + timeout)) {
 			dprintk(state->verbose, FE_ERROR, 1, "timed out!!");
 			return -ETIMEDOUT;
 		}