MIPS: smp-cmp: Fix vpe_id build error

MIPS: smp-cmp: Fix vpe_id build error

The smp-cmp build has been (further) broken since commit 856fbcee6099
("MIPS: Store core & VP IDs in GlobalNumber-style variable") in
v4.14-rc1 like so:

arch/mips/kernel/smp-cmp.c: In function ‘cmp_init_secondary’:
arch/mips/kernel/smp-cmp.c:53:4: error: ‘struct cpuinfo_mips’ has no member named ‘vpe_id’
   c->vpe_id = (read_c0_tcbind() >> TCBIND_CURVPE_SHIFT) &
    ^

Fix by replacing vpe_id with cpu_set_vpe_id().

Fixes: 856fbcee6099 ("MIPS: Store core & VP IDs in GlobalNumber-style variable")
Signed-off-by: James Hogan <jhogan@kernel.org>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17569/
Signed-off-by: James Hogan <jhogan@kernel.org>