[nrf fromlist] samples: drivers: spi_flash: Remove unnecessary Kconfig option changes

It is no longer needed to enable a specific flash driver in the sample
configuration. An appropriate driver (together with its dependecies,
like the SPI bus) for a given target will be enabled automatically
based on what is enabled in DTS.

Upstream PR #: 80042

Signed-off-by: Andrzej Głąbek <[email protected]>

Author: anangl

samples/drivers/spi_flash/boards/adafruit_feather_nrf52840_sense.conf

@@ -1,3 +1,2 @@
 CONFIG_STDOUT_CONSOLE=y
 CONFIG_FLASH=y
-CONFIG_SPI=y