pch_can: Fix bit timing calculation issue

Modify like use calculated value directly passed by CAN core module.
Signed-off-by: NTomoya MORINAGA <tomoya-linux@dsn.okisemi.com>
Acked-by: NMarc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/can/pch_can.c

@@ -786,17 +786,15 @@ static int pch_set_bittiming(struct net_device *ndev)
 	const struct can_bittiming *bt = &priv->can.bittiming;
 	u32 canbit;
 	u32 bepe;
-	u32 brp;
 
 	/* Setting the CCE bit for accessing the Can Timing register. */
 	pch_can_bit_set(&priv->regs->cont, PCH_CTRL_CCE);
 
-	brp = (bt->tq) / (1000000000/PCH_CAN_CLK) - 1;
-	canbit = brp & PCH_MSK_BITT_BRP;
+	canbit = (bt->brp - 1) & PCH_MSK_BITT_BRP;
 	canbit |= (bt->sjw - 1) << PCH_BIT_SJW_SHIFT;
 	canbit |= (bt->phase_seg1 + bt->prop_seg - 1) << PCH_BIT_TSEG1_SHIFT;
 	canbit |= (bt->phase_seg2 - 1) << PCH_BIT_TSEG2_SHIFT;
-	bepe = (brp & PCH_MSK_BRPE_BRPE) >> PCH_BIT_BRPE_BRPE_SHIFT;
+	bepe = ((bt->brp - 1) & PCH_MSK_BRPE_BRPE) >> PCH_BIT_BRPE_BRPE_SHIFT;
 	iowrite32(canbit, &priv->regs->bitt);
 	iowrite32(bepe, &priv->regs->brpe);
 	pch_can_bit_clear(&priv->regs->cont, PCH_CTRL_CCE);