tools: add VM_WARN_ON_VMG definition

tools: add VM_WARN_ON_VMG definition

vma tests compilation yields the following error:

vma.c:732:9: error: implicit declaration of function ‘VM_WARN_ON_VMG’

Fix it by adding missing VM_WARN_ON_VMG() definition.

Link: https://lkml.kernel.org/r/20250116181538.759469-1-surenb@google.com
Fixes: e3a7ae85f87c ("mm/debug: prefer VM_WARN_ON_VMG() to report VMG debug warnings")
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>