hal_flash is unused, remove the import.

All code referencing hal_flash functions was previously removed.

Signed-off-by: Blaž Hrastnik <blaz@mxxn.io>
diff --git a/boot/bootutil/src/encrypted.c b/boot/bootutil/src/encrypted.c
index 6104397..65199e5 100644
--- a/boot/bootutil/src/encrypted.c
+++ b/boot/bootutil/src/encrypted.c
@@ -14,8 +14,6 @@
 #include <string.h>
 #include <stdio.h>
 
-#include "hal/hal_flash.h"
-
 #if defined(MCUBOOT_ENCRYPT_RSA)
 #include "mbedtls/rsa.h"
 #include "mbedtls/rsa_internal.h"