Documentation PCI: Fix pciebus-howto.rst filename typo

2e642244 ("Documentation: PCI: convert PCIEBUS-HOWTO.txt to reST")
incorrectly renamed PCIEBUS-HOWTO.txt to picebus-howto.rst.

Rename it to pciebus-howto.rst.

Fixes: 2e642244 ("Documentation: PCI: convert PCIEBUS-HOWTO.txt to reST")
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Documentation/PCI/index.rst

@@ -9,7 +9,7 @@ Linux PCI Bus Subsystem
    :numbered:
 
    pci
-   picebus-howto
+   pciebus-howto
    pci-iov-howto
    msi-howto
    acpi-info