test/power: fix CPU frequency when turbo enabled

test/power: fix CPU frequency when turbo enabled

On arm platform, the value in "/sys/.../cpuinfo_cur_freq" may not
be exactly the same as what was set when using CPPC cpufreq driver.
For other cpufreq driver, no need to round it currently, or else
this check will fail with turbo enabled. For example, with acpi_cpufreq,
cpuinfo_cur_freq can be 2401000 which is equal to freqs[0].It should
not be rounded to 2400000.

Fixes: 606a234c6d360 ("test/power: round CPU frequency to check")
Cc: stable@dpdk.org
Signed-off-by: Richael Zhuang <richael.zhuang@arm.com>
Acked-by: David Hunt <david.hunt@intel.com>