[nrf noup] pm: enable ram flash partition using common flag

This patch makes mcuboot_primary_1 ram-flash partition
selectable using CONFIG_NRF53_MCUBOOT_PRIMARY_1_RAM_FLASH
property. This is needed since CONFIG_NRF53_MULTI_IMAGE_UPDATE
become not only configuration which requires that partition.

Signed-off-by: Andrzej Puzdrowski <andrzej.puzdrowski@nordicsemi.no>
(cherry picked from commit 8b3d00a)

boot/zephyr/pm.yml

@@ -73,11 +73,13 @@ mcuboot_pad:
     align: {start: CONFIG_FPROTECT_BLOCK_SIZE}
 #endif
 
-#if (CONFIG_NRF53_MULTI_IMAGE_UPDATE)
+#if (CONFIG_NRF53_MCUBOOT_PRIMARY_1_RAM_FLASH)
 mcuboot_primary_1:
   region: ram_flash
   size: CONFIG_NRF53_RAM_FLASH_SIZE
+#endif /* CONFIG_NRF53_MULTI_IMAGE_UPDATE */
 
+#if (CONFIG_NRF53_MULTI_IMAGE_UPDATE)
 mcuboot_secondary_1:
   region: external_flash
   size: CONFIG_NRF53_RAM_FLASH_SIZE