mindtct: Check for multiplication overflow in alloc_power_stats()

Assert if any of the multiplications, which are then used to allocate
memory, would overflow.

Closes: #91
2 jobs from master in 4 minutes and 1 second (queued for 17 seconds)
Status Job ID Name Coverage
  Build
passed #62529
build

00:03:05

 
  Test
passed #62530
flatpak master

00:00:55