boot: bootutil: Fix single loader trailer size

Fixes an issue introduced in commit:
  3553663
Which wrongly set the trailer size of non-swapping modes to 0

Signed-off-by: Jamie McCrae <[email protected]>

Author: nordicjm

boot/bootutil/src/bootutil_misc.c

@@ -99,12 +99,6 @@ fih_ret boot_fih_memequal(const void *s1, const void *s2, size_t n)
 static inline uint32_t
 boot_trailer_info_sz(void)
 {
-#if defined(MCUBOOT_SINGLE_APPLICATION_SLOT) ||      \
-    defined(MCUBOOT_FIRMWARE_LOADER) ||              \
-    defined(MCUBOOT_SINGLE_APPLICATION_SLOT_RAM_LOAD)
-    /* Single image MCUboot modes do not have a trailer */
-    return 0;
-#else
     return (
 #ifdef MCUBOOT_ENC_IMAGES
            /* encryption keys */
@@ -118,7 +112,6 @@ boot_trailer_info_sz(void)
            BOOT_MAX_ALIGN * 4                     +
            BOOT_MAGIC_ALIGN_SIZE
            );
-#endif
 }
 
 /*