net: ipv4: tcp: Get tcpi_count via file_count() not direct access

Commit 0a1544a1d, which implements a Qualcomm feature called
Smart Wireless Interface Manager, added a tcpi_count member to
struct tcp_info, and populates it using:

    atomic_read(&filep->f_count);

This causes compiler warnings on 64-bit architectures (e.g.,
64-bit ARCH_UM, used by net_test) because f_count is actually an
atomic_long_t, and on 64-bit architectures atomic_long_t is a
64-bit number. The difference doesn't matter in practice because
the value is cast to a __u8 anyway, but it causes build breaks
because we build with -Werror.

Instead of using atomic_long_t directly, use the the file_count
macro which exists for this purpose.

Bug: 21631098
Change-Id: Ie09a0b4e7a5cf128b21eff10c1b34faf5c995356
Signed-off-by: Lorenzo Colitti <lorenzo@google.com>
Git-Commit: fce6de568696434a22ec8f018b6a99bfec60ab1b
Git-repo: https://android.googlesource.com/kernel/msm


[jshriram@codeaurora.org: resolve minor merge conflicts]
Signed-off-by: Jeevan Shriram <jshriram@codeaurora.org>