mtd: nand: denali: remove debug lines of __FILE__, __LINE__, __func__

Such debug lines might be useful when debugging the driver first,
but should be deleted from the upstream code.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Marek Vasut <marek.vasut@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>