Fix uninitialized local variable "covered" in i386 acpi-cpufreq driver

The local variable "covered" is used without initialization in i386
acpi-cpufreq driver.  The initial value of covered should be 0.  The bug
will cause memory leak when hit.  The following patch fixes this bug.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>