arc: Rename AXS101 board to more generic AXS10x

arc: Rename AXS101 board to more generic AXS10x

As of now we have 2 flavors of ARC SDP boards:
 1) AXS101 - with ARC770 in ASIC
 2) AXS103 - with ARC HS38 in FPGA

Both options share exactly the same base-board and only differ with
CPU-tiles in use. That means all peripherals are the same (they are
implemented in FPGA on the base-board) and so generic board could be
used for both.

While at it:
 * Recreated defconfigs with savedefconfig
 * In include/configs/axs10x.h numerical sizes replaced with
defines from linux/sizes.h for better readability.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Reviewed-by: Tom Rini <trini@konsulko.com>