mtd: spi-nor: Respect flash's hwcaps in spi_nor_adjust_hwcaps()

The smart spi_nor_adjust_hwcaps() does not respect the SPI flash's
hwcaps, and only looks to the controller on what can be supported.

The flash's hwcaps needs to be AND'ed before checking.

Fixes: 71025f01 ("mtd: spi-nor-core: Rework hwcaps selection")
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>