MIPS: Netlogic: Fix assembler warning from smpboot.S

MIPS: Netlogic: Fix assembler warning from smpboot.S

The netlogic platform can be built for either MIPS32 or MIPS64, and when
built for MIPS32 (as by nlm_xlr_defconfig) the use of the dla
pseudo-instruction leads to warnings such as the following from recent
versions of the GNU assembler:

  arch/mips/netlogic/common/smpboot.S: Assembler messages:
  arch/mips/netlogic/common/smpboot.S:62: Warning: dla used to load 32-bit register; recommend using la instead
  arch/mips/netlogic/common/smpboot.S:63: Warning: dla used to load 32-bit register; recommend using la instead

Avoid these warnings by using the PTR_LA macro to make use of the
appropriate la or dla pseudo-instruction for the build.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Fixes: 66d29985fab8 ("MIPS: Netlogic: Merge some of XLR/XLP wakup code")
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jayachandran C <jchandra@broadcom.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/14185/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>