PCI: Fix MSI-HOWTO.txt info about MSI-X MMIO space

PCI: Fix MSI-HOWTO.txt info about MSI-X MMIO space

[Roland Dreier]

The current MSI-HOWTO.txt says that device drivers should not request
the memory space that contains MSI-X tables.  This is because the
original MSI-X implementation did a request_mem_region() on this
space, but that code was removed long ago (in the pre-git era, in
fact).  Years after the code was changed, we might as well clean up
the documention to avoid a confusing mention of requesting regions:
drivers using MSI-X can just use pci_request_regions() just like any
other driver, and so there's no need for MSI-HOWTO.txt to talk about
this at all.

Signed-off-by: Roland Dreier <roland@digitalvampire.org>
---
 Documentation/MSI-HOWTO.txt |    6 ++----
 1 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/Documentation/MSI-HOWTO.txt b/Documentation/MSI-HOWTO.txt
index a51f693..256defd 100644
--- a/Documentation/MSI-HOWTO.txt
+++ b/Documentation/MSI-HOWTO.txt
@@ -236,10 +236,8 @@ software system can set different pages for controlling accesses to the
 MSI-X structure. The implementation of MSI support requires the PCI
 subsystem, not a device driver, to maintain full control of the MSI-X
 table/MSI-X PBA (Pending Bit Array) and MMIO address space of the MSI-X
-table/MSI-X PBA.  A device driver is prohibited from requesting the MMIO
-address space of the MSI-X table/MSI-X PBA. Otherwise, the PCI subsystem
-will fail enabling MSI-X on its hardware device when it calls the function
-pci_enable_msix().
+table/MSI-X PBA.  A device driver should not access the MMIO address
+space of the MSI-X table/MSI-X PBA.
 
 5.3.2 API pci_enable_msix