m68k/mm: Eliminate memset after alloc_bootmem_pages

alloc_bootmem and related functions always return a zeroed region of memory.
Thus a memset after calls to these functions is unnecessary.

The following Coccinelle semantic patch was used for making the change:

@@
expression E,E1;
@@

E = \(alloc_bootmem\|alloc_bootmem_low\|alloc_bootmem_pages\|alloc_bootmem_low_pages\)(...)
... when != E
- memset(E,0,E1);

Signed-off-by: Himangi Saraogi <himangi774@gmail.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

arch/m68k/mm/init.c

@@ -94,7 +94,6 @@ void __init paging_init(void)
 	high_memory = (void *) end_mem;
 
 	empty_zero_page = alloc_bootmem_pages(PAGE_SIZE);
-	memset(empty_zero_page, 0, PAGE_SIZE);
 
 	/*
 	 * Set up SFC/DFC registers (user data space).