wifi: ipw2x00: Rename michael_mic() to libipw_michael_mic()

wifi: ipw2x00: Rename michael_mic() to libipw_michael_mic()

Rename the driver-local michael_mic() function to libipw_michael_mic()
to prevent a name conflict with the common michael_mic() function.

Note that this code will be superseded later when libipw starts using
the common michael_mic().  This commit just prevents a bisection hazard.

Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Link: https://patch.msgid.link/20260408030651.80336-2-ebiggers@kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>