cpu: Put in assertions to check for maximum supported LQ/SQ size

cpu: Put in assertions to check for maximum supported LQ/SQ size

LSQSenderState represents the LQ/SQ index using uint8_t, which supports up to
 256 entries (including the sentinel entry). Sending packets to memory with a
higher index than 255 truncates the index, such that the response matches the
wrong entry. For instance, this can result in a deadlock if a store completion
does not clear the head entry.