ARM: shmobile: Remove EMEV2 header file

There is no C board code left for the EMEV2 SoC, so
get rid of the emev2.h include file to save some lines.
While at it make functions static.

Signed-off-by: Magnus Damm <damm@opensource.se>
[horms+renesas@verge.net.au: Resolved conflict]
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>