lib/crc: Use consistent naming for CRC-32 polynomials

Header was defining CRCPOLY_LE/BE and CRC32C_POLY_LE but in fact all of
them are CRC-32 polynomials so use consistent naming.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

lib/crc: Move polynomial definition to separate header

Allow other drivers and parts of kernel to use the same define for
CRC32 polynomial, instead of duplicating it in many places. This code
does not bring any functional changes, except moving existing code.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>