checkpatch: special-case cacheline group macros

checkpatch: special-case cacheline group macros

Currently, cacheline group macros trigger checkpatch warnings.
For example:

  $ ./scripts/checkpatch.pl -g ba7e025a6c84aed012421468d83639e5dae982b0
  WARNING: Missing a blank line after declarations
  #58: FILE: drivers/gpio/gpio-virtio.c:32:
  +	struct virtio_gpio_response res;
  +	__dma_from_device_group_end();

  $ ./scripts/checkpatch.pl -g 5d4cc87414c5d11345c4b11d61377d351b5c28a2
  WARNING: Missing a blank line after declarations
  #267: FILE: include/net/sock.h:431:
  +	int			sk_rcvlowat;
  +	__cacheline_group_end(sock_read_rx);

But these are not actually statements - the following macros
all expand to zero-length fields:
  __cacheline_group_begin()
  __cacheline_group_end()
  __cacheline_group_begin_aligned()
  __cacheline_group_end_aligned()
  __dma_from_device_group_begin()
  __dma_from_device_group_end()

Add them to $declaration_macros so checkpatch recognizes this fact.

Message-ID: <b345bb7e2d4e23672e3e5d1b283754dc11c7d8cd.1767647872.git.mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>