nfc: hci: Remove unused nfc_llc_unregister

nfc_llc_unregister() has been unused since it was added in 2012's
commit 67cccfe1 ("NFC: Add an LLC Core layer to HCI")

Remove it.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/20250219020258.297995-1-linux@treblig.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>