eeprom: at25: set minimum read/write access stride to 1

SPI eeproms are addressed by byte.

Signed-off-by: Christian Eggers <ceggers@arri.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200728092959.24600-1-ceggers@arri.de


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>