fix: nand: pxa3xx: Add WA for eliminating flash ready timeout

add delay before processing the status flags in pxa3xx_nand_irq().

Signed-off-by: David Sniatkiwicz <davidsn@marvell.com>
Reviewed-by: Igal Liberman <igall@marvell.com>
Reviewed-by: Kostya Porotchkin <kostap@marvell.com>
c: Stefan Roese <sr@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Signed-off-by: Stefan Roese <sr@denx.de>