lib: crc8: pointer to data block should be const

crc8() does not change the data passed to it, so the pointer argument
should be declared const. This avoids callers that receive const data
having to cast it to a non-const pointer to call crc8().

Link: https://lkml.kernel.org/r/20210329122409.3291-1-rf@opensource.cirrus.com
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

docs: clean up and add rest of CRC functions to kernel-api.rst

Add the rest of the CRC library functions to kernel-api.

- try to clarify crc32() by adding '@' to a function parameter
- reorder kernel-api CRC functions to be less random
- add more CRC functions to kernel-api
- correct the function parameter names in several places

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

lib: crc8: add new library module providing crc8 algorithm

The brcm80211 driver in staging tree uses a crc8 function. Based on
feedback from John Linville to move this to lib directory, the linux
source has been searched. Although there is currently only one other
kernel driver using this algorithm (ie. drivers/ssb) we are providing
this as a library function for others to use.

Cc: linux-kernel@vger.kernel.org
Cc: linux-wireless@vger.kernel.org
Cc: Dan Carpenter <error27@gmail.com>
Cc: George Spelvin <linux@horizon.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Reviewed-by: Henry Ptasinski <henryp@broadcom.com>
Reviewed-by: Roland Vossen <rvossen@broadcom.com>
Reviewed-by: "Franky (Zhenhui) Lin" <frankyl@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>