MIPS: Kconfig: Select SMP symbols for CMP

CMP is an SMP implementation, and as a result of which, it needs
to select the SYS_SUPPORTS_SMP and SMP symbols. This fixes the
following build problem when CMP is enabled but SMP is not.

In file included from arch/mips/kernel/smp-cmp.c:34:0:
./arch/mips/include/asm/smp.h:26:0: error: "raw_smp_processor_id" redefined
[-Werror]
 #define raw_smp_processor_id() (current_thread_info()->cpu)
[...]
In file included from arch/mips/kernel/smp-cmp.c:34:0:
./arch/mips/include/asm/smp.h:59:20: error: redefinition of
'smp_send_reschedule'
[...]
./arch/mips/include/asm/smp.h: In function 'smp_send_reschedule':
./arch/mips/include/asm/smp.h:63:8: error: dereferencing pointer to incomplete
type

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7436/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>