thunderbolt: debugfs: Show all accessible dwords

Currently, when first failure occurs while reading of the block,
we stop reading the block and jump to the next capability.
This doesn't cover the case of block with "holes" of inaccessible
dwords, followed by accessible dwords.
This patch address this problem.
In case of failure while reading the complete block in one transaction,
(because of one or more dwords is inaccessible), we read the remaining
dwords of the block dword-by-dword, one dword per transaction,
till the end of the block.
By doing this, we handle the case of block with "holes" of inaccessible
dwords, followed by accessible dwords. The accessible dwords are shown
with the fields: <offset> <relative_offset> <cap_id> <vs_cap_id> <value>
E.g.:
0x01eb  236 0x05 0x06 0x0000d166
While the inaccesible dwords are shown as: <offset> <not accessible>
E.g.:
0x01ed <not accessible>

Signed-off-by: Gil Fine <gil.fine@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>