mtd: spi-nor: Potential oops on error path in quad_enable()

Before commit cff959958832 ("mtd: spi-nor: introduce SPI 1-2-2 and SPI
1-4-4 protocols") then we treated 1 as -EINVAL in the caller but after
that commit we changed to propagate the return.  My static checker
complains that it's eventually passed to an ERR_PTR() and later
dereferenced, but I'm not totally certain if that's true.  Regardless,
returning 1 is wrong.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>