ARM: rmobile: Update E2 Silk

ARM: rmobile: Update E2 Silk

The E2 Silk port was broken since some time. This patch updates
the E2 Silk port to use modern frameworks, DM, DT probing, SPL
for the preloading and puts it on par with the M2 Porter board.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
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NOTE: The port is missing support for I2C1 for DA9063 reset, since the
      I2C driver needs to be converted to DM and DT probing. That's not
      an issue for this patch though, since the reset was broken on Silk
      since forever.