mtd: spi-nor: Regroup flash parameter and settings

The scope is to move all [FLASH-SPECIFIC] parameters and settings
from 'struct spi_nor' to 'struct spi_nor_flash_parameter'.

'struct spi_nor_flash_parameter' describes the hardware capabilities
and associated settings of the SPI NOR flash memory. It includes
legacy flash parameters and settings that can be overwritten by the
spi_nor_fixups hooks, or dynamically when parsing the JESD216
Serial Flash Discoverable Parameters (SFDP) tables. All SFDP params
and settings will fit inside 'struct spi_nor_flash_parameter'.

Move spi_nor_hwcaps related code to avoid forward declarations.
Add a forward declaration that we can't avoid: 'struct spi_nor' will
be used in 'struct spi_nor_flash_parameter'.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Vignesh Raghavendra <vigneshr@ti.com>