clocksource/drivers/imx-tpm: Exclude sched clock for ARM64

For ARM64 platform such as i.MX8ULP which has ARMv8 generic timer as sched
clock, which is much faster compared with tpm sched clock. Reading the
tpm count register in i.MX8ULP requires about 290ns, this is slow and
introduce scheduler latency. So exclude tpm sched clock for ARM64
platform.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20220105124304.3567629-1-peng.fan@oss.nxp.com


Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>