ARM: dts: msm: Avoid conflict in I2C nodes for sdxprairie

Fix an issue where I2C nodes were being overwritten
due to redefinition. Aliases do not define new
nodes, these are defined by the node name only.
Rename the I2C nodes with alternate pin configuration
as "i2cb".

Change-Id: Ied9ee60ee8a95a7b0d7ee3e159f5b1ca89eec5f3
Signed-off-by: Gustavo Solaira <gustavos@codeaurora.org>