android: binder: refactor binder_transact()

Moved handling of fixup for binder objects,
handles and file descriptors into separate
functions.

Change-Id: If6849f1caee3834aa87d0ab08950bb1e21ec6e38
Signed-off-by: Martijn Coenen <maco@google.com>
Git-commit: 70301cb04705c846c5284910997579dee96eed41
Git-repo: https://android.googlesource.com/kernel/common


[spathi@codeaurora.org  resolved trivial merge conflicts]
Signed-off-by: Srinivasarao P <spathi@codeaurora.org>