Benjamin Herrenschmidt 7f1f6b8525 litedram: Add support for Microwatt-initialized controller
This adds support for initializing the memory controller from microwatt
rather than using a built-in RiscV processor. This might require some
fixes to LiteX and LiteDRAM (they haven't been merged as of this commit
yet).

This is enabled in the shipped generated files and can be changed via
modifying the generator script to pass False to "mw_init"

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
..
assert.h litedram: Add basic support for LiteX LiteDRAM
compiler.h litedram: Add basic support for LiteX LiteDRAM
ctype.h litedram: Add basic support for LiteX LiteDRAM
errno.h litedram: Add basic support for LiteX LiteDRAM
limits.h litedram: Add support for Microwatt-initialized controller
stdint.h litedram: Add basic support for LiteX LiteDRAM
stdio.h litedram: Add basic support for LiteX LiteDRAM
stdlib.h litedram: Add basic support for LiteX LiteDRAM
string.h litedram: Add basic support for LiteX LiteDRAM
unistd.h litedram: Add basic support for LiteX LiteDRAM