Revert "ARM: dts: msm: increase modem size as per new memory map"

This reverts commit a019aa38.
The change is required only for auto targets. Hence removing
it from common device tree file.

Change-Id: I1ba452c7123c68230a25dd296842d7124acdd152
Signed-off-by: Abinaya P <abinayap@codeaurora.org>