PCI: Change capability register offsets to hex

Convert offsets of capability registers from decimal to hex.  This matches
the spec documents and is less error prone.

[bhelgaas: also convert other capabilities with offsets > 8]
Suggested-by: Bjorn Helgaas <helgaas@kernel.org>
Link: https://lore.kernel.org/r/20210825160516.GA3576414@bjorn-Precision-5520/
Link: https://lore.kernel.org/r/aa067278adacbb59a675366052714081f4980f26.1637244780.git.baruch@tkos.co.il
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>