Currently omap onenand driver invokes gpmc_cs_request, obtains address
space allocated by gpmc to onenand. Remove this, instead use resource
structure; this is now updated with address space for onenand by gpmc
initialization with the help of gpmc_cs_request. And remove usage of
gpmc_cs_request in onenand driver.

This helps in smooth migration of gpmc to driver.
Signed-off-by: Afzal Mohammed <afzal@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>