mtd: spi-nor: spansion: Add support for Infineon S25FS256T

Infineon S25FS256T is 256Mbit Quad SPI NOR flash. The key features and
differences comparing to other Spansion/Cypress flash familes are:
  - 4-byte address mode by factory default
  - Quad mode is enabled by factory default
  - OP_READ_FAST_4B(0Ch) is not supported
  - Supports mixture of 128KB and 64KB sectors by OTP configuration
    (this patch supports uniform 128KB only due to complexity of
     non-uniform layout)

Tested on Xilinx Zynq-7000 FPGA board.

Link: https://www.infineon.com/dgdlac/Infineon-S25FS256T_256Mb_SEMPER_Nano_Flash_Quad_SPI_1.8V-DataSheet-v12_00-EN.pdf?fileId=8ac78c8c80027ecd0180740c5a46707a
Signed-off-by: Takahiro Kuwano <Takahiro.Kuwano@infineon.com>
Link: https://lore.kernel.org/r/097ef04484966593ba1326d0a99462753d7d1073.1677557525.git.Takahiro.Kuwano@infineon.com
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>