PCI/MSI: Remove unused msi_enabled_mask()

No one uses msi_enabled_mask(); remove the dead code.  No functional
change.
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/msi.c

@@ -172,11 +172,6 @@ static inline __attribute_const__ u32 msi_capable_mask(u16 control)
 	return msi_mask((control >> 1) & 7);
 }
 
-static inline __attribute_const__ u32 msi_enabled_mask(u16 control)
-{
-	return msi_mask((control >> 4) & 7);
-}
-
 /*
  * PCI 2.3 does not specify mask bits for each MSI interrupt.  Attempting to
  * mask all MSI interrupts by clearing the MSI enable bit does not work