Revert "mtd: rawnand: arasan: Prevent an unsupported configuration"

This reverts commit fc9e18f9.

This patch was a work around to fix timeout issue while operating in NVDDR
mode with software ECC engine. This patch prevents the Arasan NAND driver
from operating in NVDDR mode with software ECC engine resulting in a
significant performance degradation with SW-ECC.
'commit 7499bfee ("mtd: rawnand: arasan: Update NAND bus clock instead
of system clock")' and 'commit e16eceea ("mtd: rawnand: arasan: Fix
clock rate in NV-DDR")'
fixes the timeout issue in NVDDR mode with SW-ECC so, reverting the changes
as this work around is no longer required.

Signed-off-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@amd.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20230607053936.14306-1-amit.kumar-mahapatra@amd.com