Timing helper can be used to profile code execution from user space.
Cache invalidation is organized in tasklet and will be removed from mem
driver after some testing is performed.

Note: this is not needed any more as HW error was fixed

WIP: hw pointer offset error is still there

It looks like compessor is reporting erroneous HW pointer when last
frame ends precisely at the end of buffer and 32 zero bytes start from
the beginning of the buffer. HW pointer in this case should be 0x20, but
it is 0x00 in fact. This situation is detected and fixed in updateIRQJPEG_wp.

Conflicts resolved:
	.gitignore
	src/drivers/elphel/Kconfig
	src/drivers/elphel/Makefile
	src/include/elphel/driver_numbers.h

Remove unused initialization code and add some comments