wifi: ath12k: Use michael_mic() from cfg80211

wifi: ath12k: Use michael_mic() from cfg80211

Just use the michael_mic() function from cfg80211 instead of a local
implementation of it using the crypto_shash API.

Note: when the kernel is booted with fips=1,
crypto_alloc_shash("michael_mic", 0, 0) always returned
ERR_PTR(-ENOENT), because Michael MIC is not a "FIPS allowed" algorithm.
For now, just preserve that behavior exactly, to ensure that TKIP is not
allowed to be used in FIPS mode.  This logic actually seems to disable
the entire driver in FIPS mode and not just TKIP, but that was the
existing behavior.  Supporting this driver in FIPS mode, if anyone
actually needs it there, should be a separate commit.

Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Link: https://patch.msgid.link/20260408030651.80336-5-ebiggers@kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>