It acts as register_driver but also populates the inode size.
This allows to return a non-zero size when calling stat() on an eeprom
driver.
The conditions (CONFIG_PSEUDOFS_FILE or CONFIG_FS_SHMFS) for the
declaration of the inode size field have also been removed so that other
drivers can populate this field in the future.
Signed-off-by: Antoine Juckler <6445757+ajuckler@users.noreply.github.com>