syscall_get_arch: remove useless function arguments

Every caller of syscall_get_arch() uses current for the task and no
implementors of the function need args.  So just get rid of both of
those things.  Admittedly, since these are inline functions we aren't
wasting stack space, but it just makes the prototypes better.

Signed-off-by: Eric Paris <eparis@redhat.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mips@linux-mips.org
Cc: linux390@de.ibm.com
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Git-commit: 5e937a9ae9137899c6641d718bd3820861099a09
Git-repo: https://www.codeaurora.org/cgit/quic/la/kernel/msm


[rsiddoji@codeaurora.org: picking only ARM related changes]
Signed-off-by: Ravi Kumar Siddojigari <rsiddoji@codeaurora.org>
Change-Id: I28487cf595ce0941d67785e2d1747a4a954eb1e2
Signed-off-by: Nirmal Abraham <nabrah@codeaurora.org>