Malicious input 'index' may trigger buffer
overflow on array 'irte_alloc_bitmap[]'.
This patch validate that 'index' shall be
less than 'CONFIG_MAX_IR_ENTRIES' and also
remove unnecessary check on 'index' in
'ptirq_free_irte()' function with this fix.
Tracked-On: #6132
Signed-off-by: Yonghua Huang <yonghua.huang@intel.com>