MIPS/Xlp: Remove the dead function destroy_irq() to fix build error

MIPS/Xlp: Remove the dead function destroy_irq() to fix build error

Commit 465665f78a7 ("mips: Kill pointless destroy_irq()") removed
the destroy_irq(). So remove the leftover one in xlp_setup_msix()
to fix build error.

arch/mips/pci/msi-xlp.c: In function 'xlp_setup_msix':
arch/mips/pci/msi-xlp.c:447:3: error: implicit declaration of function 'destroy_irq'..
cc1: some warnings being treated as errors
make[1]: *** [arch/mips/pci/msi-xlp.o] Error 1
make: *** [arch/mips/pci/] Error 2

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Xinwei Hu <huxinwei@huawei.com>
Cc: Wuyun <wuyun.wu@huawei.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Russell King <linux@arm.linux.org.uk>
Cc: linux-arch@vger.kernel.org
Cc: arnab.basu@freescale.com
Cc: Bharat.Bhushan@freescale.com
Cc: x86@kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: xen-devel@lists.xenproject.org
Cc: Joerg Roedel <joro@8bytes.org>
Cc: iommu@lists.linux-foundation.org
Cc: linux-mips@linux-mips.org
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-ia64@vger.kernel.org
Cc: David S. Miller <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Liviu Dudau <liviu@dudau.co.uk>
Patchwork: https://patchwork.linux-mips.org/patch/8087/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>