Ensure core register specification is consistent when indexing bytes

[glopesdev]

Currently the following registers are specified using "bytes" and their direction is inconsistent.

First byte on the right

• R_UID
• R_TAG

First byte on the left

• R_VERSION

We should make sure the diagrams for such registers adopt a consistent orientation. Finally, the register R_DEVICE_NAME currently has no diagram, but it is unclear why this should be different from R_UID or R_TAG value (one alternative option might be to delete the diagrams from these other registers).