ANDROID: mm: build alloc_contig_dump_pages in page_alloc.o

GKI has CONFIG_DYNAMIC_DEBUG_CORE. Thus, to enable only the
specific alloc_contig_dump_pages without needing all pr_debug
in every source files is using -DCONFIG_DYNAMIC_MODULE
when the page_alloc.o compiled.

Bug: 182195592
Signed-off-by: Minchan Kim <minchan@google.com>
Change-Id: I93266eb4161b3653389c737d4c767fd5d1083339