staging: android: ion: remove duplicate buffer field initializes

As a result of various previous patches, ion_buffer_create() now
has two sets of identical statements for initializing two fields of
the buffer struct, next to each other.  Remove one set.

Move the initialization of these two fields together with the
statements that initialize the other two fields from the function
parameters, prior to the heap allocate() call, for consistency.

Signed-off-by: Todd Poynor <toddpoynor@google.com>
Acked-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>