ARM: dts: msm: update sdc1's drive strengths on 8994

All 8994 platforms are recommended to use the following drive strengths
for better signal integrity on eMMC lines.

1. CLOCK line - 16 mA
2. CMD and DATA lines - 8 mA

Change-Id: Ic5fb64628eb256b55ad8c10e224097ad5a0d3a32
Signed-off-by: Krishna Konda <kkonda@codeaurora.org>