Fix cache issues on Cortex-A7 based CPUs

The libve blobs just call IOS.mem_flush_cache() to flush caches,
so this function has to do the IOCTL_FLUSH_CACHE.

Further all data written to VE memory region has to be flushed
too.
Merge pull request #4 from jemk/master

Fix cache issues on Cortex-A7 based CPUs