ARM: S5P6440: Rename clkset_mmc_spi to clkset_group1

The clock source options avaialable in the clkset_mmc_spi are
applicable to clocks such as sclk_post, sclk_dispcon and
sclk_fimgvg. So this set is renamed as clkset_group1 to indicate
that it can be used as clock sources for other clocks and not
just for sclk_spi and sclk_mmc clocks.

Signed-off-by: Thomas Abraham <thomas.ab@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>