[ARM] qnap tsx1x: fix section mismatch

[ARM] qnap tsx1x: fix section mismatch

Fix the following warning :
WARNING: vmlinux.o(.text+0x95a0): Section mismatch in reference from the
function qnap_tsx1x_register_flash() to the (unknown reference) .init.data:(unknown)
The function qnap_tsx1x_register_flash() references
the (unknown reference) __initdata (unknown).
This is often because qnap_tsx1x_register_flash lacks a __initdata
annotation or the annotation of (unknown) is wrong.

Signed-off-by: Arnaud Patard <arnaud.patard@rtp-net.org>
Signed-off-by: Martin Michlmayr <tbm@cyrius.com>
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>