include: move find.h from asm_generic to linux

include: move find.h from asm_generic to linux

find_bit API and bitmap API are closely related, but inclusion paths are
different - include/asm-generic and include/linux, correspondingly.  In
the past it made a lot of troubles due to circular dependencies and/or
undefined symbols.  Fix this by moving find.h under include/linux.

Link: https://lkml.kernel.org/r/20210814211713.180533-4-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>