Allows `MICROPY_HW_QSPIFLASH_SIZE_BITS_LOG2` and
`MICROPY_HW_QSPI_MPU_REGION_SIZE` to be arbitrary expressions, eg function
calls.
The `storage.h` header needs to be included in case access to `spi_bdev_t`
is needed by the macros.
Signed-off-by: Damien George <damien@micropython.org>