msm: Do not use offset, when reporting image version string

As per requirements we have to report untouched image version string,
which includes numbers before the string: "00:BOOT.BF.2.1-2.1.0890",
instead of "BOOT.BF.2.1-2.1.0890".

Change-Id: I14ed75ef388daa23c108d8ec6dbcb7b4c2fc2fe8
Signed-off-by: Yulian Shandorov <jshandorov@codeaurora.org>