[Backup & Restore] Performance changes

- Use always aligned buffers to up the speed for DMA usage. For verification, backup and restore.
- Rework verification a little bit and make default Sparse mode.

Sparse mode protects from fake sd cards, bad sectors and frequent I/O corruption. Aka, ~100% of cases.

bootloader/utils/util.h

@@ -41,8 +41,4 @@ void power_off();
 void exec_cfg(u32 *base, const cfg_op_t *ops, u32 num_ops);
 u32 crc32c(const void *buf, u32 len);
 
-/* This is a faster implementation of memcmp that checks two u32 values */
-/* every 128 Bytes block. Intented only for Backup and Restore          */
-u32 memcmp32sparse(const u32 *buf1, const u32 *buf2, u32 len);
-
 #endif