test_static_idt: fix unininitialized variable

The divide-by-zero test was using an uninitialized variable that
Coverity was unhappy about. Simple fix to just initialize to any non
zero value.

Change-Id: I9e5865a99e7a8eb3ee52421cc3dcb6717dca1ad1
Coverity-ID: 152053
Signed-off-by: Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>