[nrf fromtree] drivers/flash/Kconfig.nrf_rram: bufferd write by default

Enable buffered write for nRF54l RRAM flash driver by default.
CONFIG_NRF_RRAM_WRITE_BUFFER_SIZE=1 means that write will be buffered
by 16 B buffer (native RRAM write-bock-size).
This allows optimal life-endurance of RRAM memory.

For reference" DTS declares 16 write-block-size already.

Signed-off-by: Andrzej Puzdrowski <andrzej.puzdrowski@nordicsemi.no>
(cherry picked from commit 2cea407)

drivers/flash/Kconfig.nrf_rram

@@ -24,7 +24,7 @@ if SOC_FLASH_NRF_RRAM
 config NRF_RRAM_WRITE_BUFFER_SIZE
 	int "Internal write-buffer size"
 	default 32 if !SOC_FLASH_NRF_RADIO_SYNC_NONE
-	default 0
+	default 1
 	range 0 32
 	help
 	  Number of 128-bit words.