mtd: spinand: propagate spinand_wait() errors from spinand_write_page()

Since commit 3d1f08b0 ("mtd: spinand: Use the external ECC engine
logic") the spinand_write_page() function ignores the errors returned
by spinand_wait(). Change the code to propagate those up to the stack
as it was done before the offending change.

Cc: stable@vger.kernel.org
Fixes: 3d1f08b0 ("mtd: spinand: Use the external ECC engine logic")
Signed-off-by: Gabor Juhos <j4g8y7@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>