mtd: onenand: omap2: Do not make delay for GPIO OMAP3 specific

Second commit in driver history (782b7a36: "[MTD] [OneNAND] OMAP3:
add delay for GPIO") added quirk for waiting until GPIO line settle.
As DMA was disabled for OMAP2 boards, chances are this problem was
not OMAP3 specific and as it is just one register read, previous
test for SoC type is approximately as expensive as read itself.
Make delay unconditional, which allows removing SoC specific code
alltogether.

Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Acked-by: Roger Quadros <rogerq@ti.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>