staging: rtlwifi: Remove empty halmac_pcie_reg.h

halmac_pcie_reg.h is empty, so remove it and the only include of it.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>