ARM: shmobile: Remove unused r8a7740_init_delay()

Remove the now unused r8a7740_init_delay() function.

Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
Tested-by: Geert Uytterhoeven <geert@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>