util: Cleaned up lfs_util.h

This one was a bit more involved.

Removes utils that are no longer useful, and made sure some of the
name/API changes over time are adopted consistently:

- lfs_npw2 -> lfs_nlog2
- lfs_tole32_ -> lfs_tole32
- lfs_fromle32_ -> lfs_fromle32

Also did another pass for lfs_ prefixes on mem/str functions. The habit
to use the naked variants of these is hard to break!

lfs_util.c

@@ -57,26 +57,6 @@ ssize_t lfs_fromleb128(uint32_t *word, const void *buffer, size_t size) {
 }
 
 
-//// Software CRC implementation with small lookup table
-//uint32_t lfs_crc(uint32_t crc, const void *buffer, size_t size) {
-//    static const uint32_t rtable[16] = {
-//        0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
-//        0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
-//        0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c,
-//        0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c,
-//    };
-//
-//    const uint8_t *data = buffer;
-//
-//    for (size_t i = 0; i < size; i++) {
-//        crc = (crc >> 4) ^ rtable[(crc ^ (data[i] >> 0)) & 0xf];
-//        crc = (crc >> 4) ^ rtable[(crc ^ (data[i] >> 4)) & 0xf];
-//    }
-//
-//    return crc;
-//}
-
-
 // crc32c tables (see lfs_crc32c for more info)
 #if !defined(LFS_SMALLER_CRC32C) \
         && !defined(LFS_FASTER_CRC32C) \
@@ -301,4 +281,5 @@ uint32_t lfs_crc32c_mul(uint32_t a, uint32_t b) {
     return (uint32_t)r;
 }
 
+
 #endif