pwm: rcar: Simplify multiplication/shift logic

- Remove the superfluous cast; the multiplication will yield a 64-bit
result due to the "100ULL" anyway,
- "a * (1 << b)" == "a << b".

Signed-off-by: Geert Uytterhoeven <[e-mail]>
Reviewed-by: Uwe Kleine-König <[e-mail]>
Signed-off-by: Thierry Reding <[e-mail]>

drivers/pwm/pwm-rcar.c

···
 	unsigned long clk_rate = clk_get_rate(rp->clk);
 	u32 cyc, ph;
 
-	one_cycle = (unsigned long long)NSEC_PER_SEC * 100ULL * (1 << div);
+	one_cycle = NSEC_PER_SEC * 100ULL << div;
 	do_div(one_cycle, clk_rate);
 
 	tmp = period_ns * 100ULL;