kernel: fix busy wait loop in mediatek PPE code

The intention is for the loop to timeout if the body does not succeed.
The current logic calls time_is_before_jiffies(timeout) which is false
until after the timeout, so the loop body never executes.

time_is_after_jiffies(timeout) will return true until timeout is less
than jiffies, which is the intended behavior here.

Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>

target/linux/generic/pending-5.4/770-15-net-ethernet-mediatek-mtk_eth_soc-add-support-for-in.patch

@@ -183,7 +183,7 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
 +{
 +	unsigned long timeout = jiffies + HZ;
 +
-+	while (time_is_before_jiffies(timeout)) {
++	while (time_is_after_jiffies(timeout)) {
 +		if (!(ppe_r32(ppe, MTK_PPE_GLO_CFG) & MTK_PPE_GLO_CFG_BUSY))
 +			return 0;
 +