Replace flash partitioning terminology

This change replaces the slot 0/1 terminology with primary/secondary
slot and replaces FLASH_AREA_IMAGE_0/1 with
FLASH_AREA_IMAGE_PRIMARY/SECONDARY. This naming convention may be more
understandable, fits better to MCUs with multiple images and it is an
architecture agnostic alternative as well.

Change-Id: I655a585f6ae023852c671ee6635399efe25209c9
Signed-off-by: David Vincze <david.vincze@arm.com>
Signed-off-by: David Brown <david.brown@linaro.org>
diff --git a/boot/zephyr/Kconfig b/boot/zephyr/Kconfig
index 29193d1..4e75cef 100644
--- a/boot/zephyr/Kconfig
+++ b/boot/zephyr/Kconfig
@@ -72,11 +72,11 @@
 	default "mcuboot-mbedtls-cfg.h"
 
 config BOOT_VALIDATE_SLOT0
-	bool "Validate image slot 0 on every boot"
+	bool "Validate image in the primary slot on every boot"
 	default y
 	help
-	  If y, the bootloader attempts to validate the signature of
-	  slot0 every boot.  This adds the signature check time to
+	  If y, the bootloader attempts to validate the signature of the
+	  primary slot every boot. This adds the signature check time to
 	  every boot, but can mitigate against some changes that are
 	  able to modify the flash image itself.
 
@@ -84,25 +84,25 @@
 	bool "Overwrite image updates instead of swapping"
 	default n
 	help
-	  If y, overwrite slot0 with the upgrade image instead of
-	  swapping them.  This prevents the fallback recovery, but
+	  If y, overwrite the primary slot with the upgrade image instead
+	  of swapping them. This prevents the fallback recovery, but
 	  uses a much simpler code path.
 
 config BOOT_BOOTSTRAP
-	bool "Boostrap erased slot0 from slot1"
+	bool "Boostrap erased the primary slot from the secondary slot"
 	default n
 	help
 	  If y, enables bootstraping support. Bootstrapping allows an erased
-	  slot0 to be initialized from a valid image in slot1.
+	  primary slot to be initialized from a valid image in the secondary slot.
 	  If unsure, leave at the default value.
 
 config BOOT_ENCRYPT_RSA
 	bool "Support for encrypted upgrade images"
 	default n
 	help
-	  If y, images in slot 1 can be encrypted and are decrypted
-	  on the fly when upgrading to slot 0, as well as encrypted
-	  back when swapping from slot 0 to slot 1.
+	  If y, images in the secondary slot can be encrypted and are decrypted
+	  on the fly when upgrading to the primary slot, as well as encrypted
+	  back when swapping from the primary slot to the secondary slot.
 
 config BOOT_MAX_IMG_SECTORS
 	int "Maximum number of sectors per image slot"