find: micro-optimize for_each_{set,clear}_bit()

find: micro-optimize for_each_{set,clear}_bit()

The macros iterate thru all set/clear bits in a bitmap.  They search a
first bit using find_first_bit(), and the rest bits using find_next_bit().

Since find_next_bit() is called shortly after find_first_bit(), we can
save few lines of I-cache by not using find_first_bit().

Link: https://lkml.kernel.org/r/20210814211713.180533-12-yury.norov@gmail.com
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: Alexander Lobakin <alobakin@pm.me>
Cc: Alexey Klimov <aklimov@redhat.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>