nand: mxc: Fix debug trace in mxc_nand_read_oob_syndrome()

The page number indicated in the debug trace of mxc_nand_read_oob_syndrome() did
not match the page being worked on.

By the way, replace the GCC-specific __FUNCTION__ with __func__.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Acked-by: Scott Wood <scottwood@freescale.com>