cxgb4: remove bogus CHELSIO_VPD_UNIQUE_ID constant

The comment is quite weird, there is no such thing as a vendor-specific
VPD id. 0x82 is the value of PCI_VPD_LRDT_ID_STRING. So what we are
doing here is simply checking whether the byte at VPD address VPD_BASE
is a valid string LRDT, same as what is done a few lines later in
the code.
LRDT = Large Resource Data Tag, see PCI 2.2 spec, VPD chapter

v2:
- don't set VPD_BASE / VPD_BASE_OLD separately

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/644ef22f-e86a-5cc1-0f27-f873ab165696@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>