platform: ferrum: Remove function declaration of qtmr_irq.

qtmr_irq was required for msm8916,to maintain image
compatibility between 8916 and 8939,by assigning the qtimer
irq number according to the target. It is not required for
ferrum.

Change-Id: I521af46bbc24731bdc0ab7abee2797286721d07b
1 file changed