arc770: Update kernel configuration

Now when we're switching to FS on SD-card it's necessary to have
full stack of MMC block & FC drivers built-in otherwise kernel won't
be able to mount FS with needed modules.

Also we enable parsing of input parameters passed to the kernel by
U-Boot. Otherwise kernel won't know where to look for command line and
what's worse device tree blob (we had to disable this by default for
cases when kernel is loaded by JTAG and core registers may have
undefined state lading to kernel going bonkers).

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>