arm/dt: msm8974: Set 8-bit mode for eMMC

eMMC 8-bit communication in HS200 on v1 Fluids has had data CRC errors
due to possible cross-talk between the data lines. As a result the bus
width for fluids has been limited to 4 instead of 8. As a result the
performance has reduced.

The v2 Fluids do not have any such problems and performance on those
should not be penalized. So enable 4-bit bus mode only for v1 Fluids.

CRs-Fixed: 459298
Change-Id: Ia85e4e99870b94f12128b70a1229be7a074c12aa
Signed-off-by: Krishna Konda <kkonda@codeaurora.org>