boot: zephyr: Fix serial recovery for NXP IMX.RT platforms

Serial recovery failed for NXP IMX.RT platforms
unless BOOT_ERASE_PROGRESSIVELY is set.

Signed-off-by: Andrej Butok <andrey.butok@nxp.com>

boot/zephyr/Kconfig.serial_recovery

@@ -98,7 +98,7 @@ config BOOT_SERIAL_MAX_RECEIVE_SIZE
 
 config BOOT_ERASE_PROGRESSIVELY
 	bool "Erase flash progressively when receiving new firmware"
-	default y if SOC_FAMILY_NORDIC_NRF
+	default y if SOC_FAMILY_NORDIC_NRF || SOC_FAMILY_NXP_IMXRT
 	help
 	 If enabled, flash is erased as necessary when receiving new firmware,
 	 instead of erasing the whole image slot at once. This is necessary