Adding support for MX25L6455EMI

[The Raven]

Hi

I have two of those chips and added support for them.
This chip looks similar to the "MX25L6406E", so i took this part of code
and modified it to fit the MX25L6455EMI.

I have tested all erase modes (logs available if needed).
spi_block_erase_20
spi_block_erase_52
spi_block_erase_d8
spi_block_erase_60
spi_block_erase_c7

I am not a coder and it's years ago since my last patch. So sorry for
not posting a patch. :-(

Here are my modifications (are the correct?):

File flashchips.h
#define MACRONIX_MX25L6455EMI    0x2617    /* MX25L6455EMI (4k 0x20) */

File flashchips.c
{
        .vendor        = "Macronix",
        .name        = "MX25L6455EMI",
        .bustype    = BUS_SPI,
        .manufacture_id    = MACRONIX_ID,
        .model_id    = MACRONIX_MX25L6455EMI,
        .total_size    = 8192,
        .page_size    = 256,
        .feature_bits    = FEATURE_WRSR_WREN | FEATURE_OTP,
        .tested        = TEST_OK_PREW,
        .probe        = probe_spi_rdid,
        .probe_timing    = TIMING_ZERO,
        .block_erasers    =
        {
            {
                .eraseblocks = { {4 * 1024, 2048} },
                .block_erase = spi_block_erase_20,
            }, {
                .eraseblocks = { {64 * 1024, 128} },
                .block_erase = spi_block_erase_52,
            }, {
                .eraseblocks = { {64 * 1024, 128} },
                .block_erase = spi_block_erase_d8,
            }, {
                .eraseblocks = { {8 * 1024 * 1024, 1} },
                .block_erase = spi_block_erase_60,
            }, {
                .eraseblocks = { {8 * 1024 * 1024, 1} },
                .block_erase = spi_block_erase_c7,
            }
        },
        .printlock    = spi_prettyprint_status_register_bp3_srwd,
        .unlock        = spi_disable_blockprotect_bp3_srwd,
        .write        = spi_chip_write_256,
        .read        = spi_chip_read, /* Fast read (0x0B), dual I/O read
supported */
        .voltage    = {2700, 3600},
    },