mmc: sdhci-msm: Add software capabilities for voltage init

With SDCC5 the capabilities register is not advertising the
3.0 voltage features (except for 8974 and 8084).

So add the software capabilities for voltage initialization
for rest of the targets with SDCC5.

CRs-Fixed: 568227
Change-Id: Ida53f5ad7249cd0cd8428b4839dfd932b04e31fa
Signed-off-by: Pratibhasagar V <pratibha@codeaurora.org>
[xiaonian@codeaurora.org: fix trivial merge conflict]
Signed-off-by: Xiaonian Wang <xiaonian@codeaurora.org>