ARM: shmobile: Remove obsolete earlytimer registration

The last caller of shmobile_earlytimer_init() was removed in commit
c99cd90d

 ("ARM: shmobile: r8a7779: Remove legacy SoC code").

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>