msm: msm_rq_stats: remove is_smp() API

is_smp() API is unavailable on few target codes.
Until this API is defined use CONFIG_SMP to know
whether target supports SPM are not.

CRs-fixed: 579034
Change-Id: I5bd5c208b18aae27d7f36e77e9d5b38639c2c00e
Signed-off-by: Murali Nalajala <mnalajal@codeaurora.org>