mtd: revert "spi-nor: intel: provide a range for poll_timout"

mtd: revert "spi-nor: intel: provide a range for poll_timout"

This change reverts aba3a882a178: "mtd: spi-nor: intel: provide a range
for poll_timout". That change introduces a performance regression when
reading sequentially from flash. Logging calls to intel_spi_read without
this change we get:

Start MTD read
[   20.045527] intel_spi_read(from=1800000, len=400000)
[   20.045527] intel_spi_read(from=1800000, len=400000)
[  282.199274] intel_spi_read(from=1c00000, len=400000)
[  282.199274] intel_spi_read(from=1c00000, len=400000)
[  544.351528] intel_spi_read(from=2000000, len=400000)
[  544.351528] intel_spi_read(from=2000000, len=400000)
End MTD read

With this change:

Start MTD read
[   21.942922] intel_spi_read(from=1c00000, len=400000)
[   21.942922] intel_spi_read(from=1c00000, len=400000)
[   23.784058] intel_spi_read(from=2000000, len=400000)
[   23.784058] intel_spi_read(from=2000000, len=400000)
[   25.625006] intel_spi_read(from=2400000, len=400000)
[   25.625006] intel_spi_read(from=2400000, len=400000)
End MTD read

Signed-off-by: Luis Alberto Herrera <luisalberto@google.com>
Tested-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Link: https://lore.kernel.org/r/20200610224652.64336-1-luisalberto@google.com
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>