Fix zdb_dump_block for little endian

[tuxoko]

Motivation and Context

The endian macros were changed but zdb_dump_block wasn't updated accordingly.

Description

How Has This Been Tested?

Before the change

$ sudo zdb -R pp 0:20000c000:200
Found vdev: /dev/sdb1

0:20000c000:200
          0 1 2 3 4 5 6 7   8 9 a b c d e f  0123456789abcdef
000000:  00cc0403002f505a  0000000000000101  ZP/.............

After the change

$ sudo zdb -R pp 0:20000c000:200
Found vdev: /dev/sdb1

0:20000c000:200
          0 1 2 3 4 5 6 7   8 9 a b c d e f  0123456789abcdef
000000:  5a502f000304cc00  0101000000000000  ZP/.............

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Performance enhancement (non-breaking change which improves efficiency)
• [ ] Code cleanup (non-breaking change which makes code smaller or more readable)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] Library ABI change (libzfs, libzfs_core, libnvpair, libuutil and libzfsbootenv)
• [ ] Documentation (a change to man pages or other documentation)

Checklist:

• [x] My code follows the OpenZFS code style requirements.
• [ ] I have updated the documentation accordingly.
• [x] I have read the contributing document.
• [ ] I have added tests to cover my changes.
• [ ] I have run the ZFS Test Suite with this change applied.
• [x] All commit messages are properly formatted and contain Signed-off-by.