spi-nor: intel-spi: Remove EXPERT dependency

The idea to have the intel-spi driver dependent on EXPERT was exactly
because we did not want ordinary users playing with the device and
inadvertently overwrite their BIOSes (if it is not protected). This
seems to be superfluous hence remove it.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>