power: qpnp-fg-gen4: Initialize work and mutex locks early

Currently, all the works are cancelled in fg_gen4_cleanup when it
is invoked when the driver probe fails. When the works are
cancelled even before they're initialized, a warning is printed
out from debug objects. Fix this by initializing them earlier.

Change-Id: Ibe73dd1e7f5aef65b30c331d7878b7dc83b85205
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>