Staging: android: Mark local functions in binder.c as static

This fixes the following sparse warnings
drivers/staging/android/binder.c:1703:5: warning: symbol 'binder_thread_write' was not declared. Should it be static?
drivers/staging/android/binder.c:2058:6: warning: symbol 'binder_stat_br' was not declared. Should it be static?

Change-Id: I930f10e54c19b0c6aca275f3ef51320bcfa3bb34
Signed-off-by: Bojan Prtvar <prtvar.b@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Git-commit: fb07ebc3e82a98a3605112b71ea819c359549c4b
Git-repo: https://android.googlesource.com/kernel/common/


Signed-off-by: Neeti Desai <neetid@codeaurora.org>
Signed-off-by: Ajay Dudani <adudani@codeaurora.org>