[nrf fromtree] bootutil: Temporarly drop mem cleanup from boot_state_clear

Temporal removal of memset clear of boot_sector_clear that
was causing boot to stop.
The problem happens due to fill_rsp assigning pointer to header
stored in cleared boot_state object, and the memset makes it inaccessible.

Once change where header is copied to rsp the memset should be brought
back as the boot_loader state should be completed before we pass
further in execution.

Fixes #2535

(cherry picked from commit e6fefac)
Signed-off-by: Dominik Ermel <dominik.ermel@nordicsemi.no>

Author: de-nordic

boot/bootutil/src/bootutil_misc.c

@@ -713,6 +713,7 @@ void boot_state_clear(struct boot_loader_state *state)
             boot_enc_drop(&state->enc[image][slot]);
         }
     }
+#else
+    (void)state;
 #endif
-    memset(state, 0, sizeof(struct boot_loader_state));
 }