Revert "ARM: dts: msm: i2c: change clock rate to 19.2 MHz"

This reverts commit b4bae3a760274ee281bfa6260f4fd13323553bf0.
Revert "arch/arm/boot/dts/msm8974.dtsi: set other i2c clocks to 19.2 MHz as well"

This reverts commit 530d4d402c1a029861f1b0c457c399896150b491.