mtd: spi-nor : Remove SPI_NOR_HAS_TB flag on s25fl512s

Currently, the Top/Bottom protection function (SPI_NOR_HAS_TB) is
implemented to fit some flashes with TB bit on SR.

s25fl512s has TBPROT bit on CR1, so the TB protection is not working on it.
Fix the wrong flag on s25fl512s.

Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>