memory: omap-gpmc: Fix debug output for access width

The width needs to be configured in bytes with 1 meaning 8-bit
access and 2 meaning 16-bit access.

Cc: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>