ARM: vfpmodule: Move bounce stats file to seq_file and friends

In future kernels create_proc_entry() is going to be removed.
Let's modernize this code and use regular file operations and
seq_printf() to avoid experiencing compilation problems in future
kernels.

Change-Id: Ie53663e099ff72a3eec84df7c3f77e15c0e539be
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>