xz: cleanup CRC32 edits from 2018

In 2018, a dependency on <linux/crc32poly.h> was added to avoid
duplicating the same constant in multiple files. Two months later it was
found to be a bad idea and the definition of CRC32_POLY_LE macro was moved
into xz_private.h to avoid including <linux/crc32poly.h>.

xz_private.h is a wrong place for it too. Revert back to the upstream
version which has the poly in xz_crc32_init() in xz_crc32.c.

Link: https://lkml.kernel.org/r/20240721133633.47721-10-lasse.collin@tukaani.org
Fixes: faa16bc404d7 ("lib: Use existing define with polynomial")
Fixes: 242cdad873a7 ("lib/xz: Put CRC32_POLY_LE in xz_private.h")
Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Reviewed-by: Sam James <sam@gentoo.org>
Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Joel Stanley <joel@jms.id.au>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jubin Zhong <zhongjubin@huawei.com>
Cc: Jules Maselbas <jmaselbas@zdiv.net>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Rui Li <me@lirui.org>
Cc: Simon Glass <sjg@chromium.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>