mm/page_alloc.c: simplify the code by using macro K()

Use helper macro K() to convert the pages to the corresponding size.
Minor readability improvement.

Link: https://lkml.kernel.org/r/20210902121242.41607-3-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/page_alloc.c

@@ -8130,8 +8130,7 @@ unsigned long free_reserved_area(void *start, void *end, int poison, const char
 	}
 
 	if (pages && s)
-		pr_info("Freeing %s memory: %ldK\n",
-			s, pages << (PAGE_SHIFT - 10));
+		pr_info("Freeing %s memory: %ldK\n", s, K(pages));
 
 	return pages;
 }
@@ -8176,14 +8175,13 @@ void __init mem_init_print_info(void)
 		", %luK highmem"
 #endif
 		")\n",
-		nr_free_pages() << (PAGE_SHIFT - 10),
-		physpages << (PAGE_SHIFT - 10),
+		K(nr_free_pages()), K(physpages),
 		codesize >> 10, datasize >> 10, rosize >> 10,
 		(init_data_size + init_code_size) >> 10, bss_size >> 10,
-		(physpages - totalram_pages() - totalcma_pages) << (PAGE_SHIFT - 10),
-		totalcma_pages << (PAGE_SHIFT - 10)
+		K(physpages - totalram_pages() - totalcma_pages),
+		K(totalcma_pages)
 #ifdef	CONFIG_HIGHMEM
-		, totalhigh_pages() << (PAGE_SHIFT - 10)
+		, K(totalhigh_pages())
 #endif
 		);
 }