PCI: spear: Remove spear13xx_pcie_remove()

Following compilation warning occurs when compiled with:
CONFIG_DEBUG_SECTION_MISMATCH=y

 WARNING: vmlinux.o(.init.data+0x3338): Section mismatch in reference from the
 variable spear13xx_pcie_driver to the function
 .exit.text:spear13xx_pcie_remove()

This driver isn't allowed to unload, and so doesn't have a *_exit() routine. But
it still has spear13xx_pcie_remove() marked with __exit.

As this driver can't unload, .remove() would never be called, right? So get rid
of it.

Fixes: 51b66a6c

 (PCI: spear: Add PCIe driver for ST Microelectronics SPEAr13xx)
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>