ARM: shmobile: defconfig: Enable CONFIG_PRINTK_TIME

Enable timestamps for kernel log output to improve debugging.
You can always use "dmesg -t" to strip the timestamps.

Don't specify CONFIG_LOG_BUF_SHIFT=16 while we're at it.  There's a
reason the default in Kconfig is higher ;-)

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