msm: camera: isp: Enable Bus Read only for fetch engine

Changes to enable bus read for fetch engine only during
fetch engine configuration is done.
Removed go cmd from reload command as it was causing,
causing page fault.

Change-Id: I60a5b89c6286a6b8c0d80e753a1d2c722cac21a9
Signed-off-by: Sagar Gore <sgore@codeaurora.org>