gateware/icE1usb: Replace local I2C core with no2misc one

This core has been merged (and improved) upstream, so
update the submodule, remove local copy and make the required
tweaks.

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
Change-Id: I79fca561fee32bbaec94882b4f65c7ecaa44be11
5 files changed