SH: fix TS field shift calculation for DMA drivers

CHCR_TS_HIGH_SHIFT is defined as a shift of TS high bits in CHCR register,
relative to low bits. The TS_INDEX2VAL() macro has to take this into account.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>