MIPS: CPC: Remove "weak" from mips_cpc_phys_base() and make it static

MIPS: CPC: Remove "weak" from mips_cpc_phys_base() and make it static

There's only one implementation of mips_cpc_phys_base(), and it's only used
within the same file, so it doesn't need to be weak, and it doesn't need an
extern declaration.

Remove the extern mips_cpc_phys_base() declaration and make it static.

[ralf@linux-mips.org: Fixed conflict.]

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: linux-mips@linux-mips.org
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10681/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>