msm: qmi: Do not reserve TLV space twice while encoding nested structures

While encoding nested structures, space is reserved redundantly in QMI
message wire format for storing type and length information. Avoid the
redundant reservation of space.

Change-Id: I00164375501056cc4a3b807af3e7eee638ba758c
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>