power: reset: fix compilation errors when dload disabled.

If download mode disabled, msm-poweroff driver compilation will
throw errors.
Fix them by moving download mode support under the flag.

Change-Id: I7a3f946d72cb4e500e3e762e4a6a5f2c8b90cb8c
Signed-off-by: Lingutla Chandrasekhar <clingutla@codeaurora.org>