nfc: trf7970a: drop unneeded debug prints

ftrace is a preferred and standard way to debug entering and exiting
functions so drop useless debug prints.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Acked-by: Mark Greer <mgreer@animalcreek.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>