Documentation: PCI: Fix typo in pci-error-recovery.rst

Replace "It" with "If", since it is a conditional statement.

Link: https://lore.kernel.org/r/20210531081215.43507-1-wesley.sheng@amd.com


Signed-off-by: Wesley Sheng <wesley.sheng@amd.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Krzysztof Wilczyński <kw@linux.com>