clk: fractional-divider: Use bit operations consistently

Use BIT() where makes sense. This alings usage of bit operations
in the same pieces of code. Moreover, strictly speaking by the
letter of the C standard, left shift of 1 by 31 bits is UB (undefined
behaviour), switching to BIT() addresses that as well.

Signed-off-by: Andy Shevchenko <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Reviewed-by: Chen-Yu Tsai <[e-mail]>
Signed-off-by: Stephen Boyd <[e-mail]>

drivers/clk/clk-fractional-divider.c

···
 	}
 
 	if (fd->flags & CLK_FRAC_DIVIDER_ZERO_BASED) {
-		max_m = 1 << fd->mwidth;
-		max_n = 1 << fd->nwidth;
+		max_m = BIT(fd->mwidth);
+		max_n = BIT(fd->nwidth);
 	} else {
 		max_m = GENMASK(fd->mwidth - 1, 0);
 		max_n = GENMASK(fd->nwidth - 1, 0);
···
 	u32 val;
 
 	if (fd->flags & CLK_FRAC_DIVIDER_ZERO_BASED) {
-		max_m = 1 << fd->mwidth;
-		max_n = 1 << fd->nwidth;
+		max_m = BIT(fd->mwidth);
+		max_n = BIT(fd->nwidth);
 	} else {
 		max_m = GENMASK(fd->mwidth - 1, 0);
 		max_n = GENMASK(fd->nwidth - 1, 0);