clk-divider: fix macros

The macro is_power_of_two() in clk-divider.c was defined as !(i & ~i)
which is always true.  Instead use is_power_of_2() from log2.h.

Also add brackets around the macro arguments in div_mask to avoid any
future operator precedence problems.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: use log2.h per Joe Perches; update changelog]

drivers/clk/clk-divider.c

@@ -16,6 +16,7 @@
 #include <linux/io.h>
 #include <linux/err.h>
 #include <linux/string.h>
+#include <linux/log2.h>
 
 /*
  * DOC: basic adjustable divider clock that cannot gate
@@ -29,8 +30,7 @@
 
 #define to_clk_divider(_hw) container_of(_hw, struct clk_divider, hw)
 
-#define div_mask(d)	((1 << (d->width)) - 1)
-#define is_power_of_two(i)	!(i & ~i)
+#define div_mask(d)	((1 << ((d)->width)) - 1)
 
 static unsigned int _get_table_maxdiv(const struct clk_div_table *table)
 {
@@ -137,7 +137,7 @@ static bool _is_valid_table_div(const struct clk_div_table *table,
 static bool _is_valid_div(struct clk_divider *divider, unsigned int div)
 {
 	if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
-		return is_power_of_two(div);
+		return is_power_of_2(div);
 	if (divider->table)
 		return _is_valid_table_div(divider->table, div);
 	return true;