ARM: S5P64X0: Fix iodesc array size for S5P6450

The array size parameter of iotable_init for S5P6450 is incorrect.
Fix this by passing the correct length of s5p6450_iodesc table.

Signed-off-by: Banajit Goswami <banajit.g@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>