mcuboot serial recovery wholly broken for single slot modes

[nordicjm]

The recent fix for image state null introduced code that calls various functions like boot_open_all_flash_areas which are added in loader.c, however, there's a bunch of MCUboot modes that do not use this file e.g. single slot, single ram load mode so when you configure MCUboot in one of these mode with serial recovery mode, you get the following:

/opt/zephyr-sdk-0.17.0/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd: zephyr/libzephyr.a(boot_serial.c.obj): in function `bs_list_set':
/tmp/cc/bootloader/mcuboot/boot/boot_serial/src/boot_serial.c:657: undefined reference to `boot_state_clear'
/opt/zephyr-sdk-0.17.0/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd: /tmp/cc/bootloader/mcuboot/boot/boot_serial/src/boot_serial.c:659: undefined reference to `boot_open_all_flash_areas'
/opt/zephyr-sdk-0.17.0/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd: /tmp/cc/bootloader/mcuboot/boot/boot_serial/src/boot_serial.c:670: undefined reference to `boot_read_sectors'
/opt/zephyr-sdk-0.17.0/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd: /tmp/cc/bootloader/mcuboot/boot/boot_serial/src/boot_serial.c:691: undefined reference to `boot_close_all_flash_areas'
/opt/zephyr-sdk-0.17.0/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd: /tmp/cc/bootloader/mcuboot/boot/boot_serial/src/boot_serial.c:691: undefined reference to `boot_close_all_flash_areas'
/opt/zephyr-sdk-0.17.0/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd: /tmp/cc/bootloader/mcuboot/boot/boot_serial/src/boot_serial.c:691: undefined reference to `boot_close_all_flash_areas'
collect2: error: ld returned 1 exit status

[nordicjm]

@taltenbach your changes introduced this, can you look at this? This is a huge regression never mind have fixed it myself