ARM: amlogic: add sm efuse write support and cmd for read/write efuse

This adds support for amlogic efuse write and provides two subcommands
of "sm" command: "efuseread" and "efusewrite" to read/write bytes between
memory and efuse.

Signed-off-by: Vyacheslav Bocharov <adeep@lexina.in>
[narmstrong: fixed indent at end of patch]
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>