x86: remove unnecessary memset and NULL check after alloc_bootmem()

memset and NULL check after alloc_bootmem() are unnecessary.
Because it returns zeroed memory and it never return NULL.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/acpi/boot.c

@@ -697,10 +697,6 @@ static int __init acpi_parse_hpet(struct acpi_table_header *table)
 #define HPET_RESOURCE_NAME_SIZE 9
 	hpet_res = alloc_bootmem(sizeof(*hpet_res) + HPET_RESOURCE_NAME_SIZE);
 
-	if (!hpet_res)
-		return 0;
-
-	memset(hpet_res, 0, sizeof(*hpet_res));
 	hpet_res->name = (void *)&hpet_res[1];
 	hpet_res->flags = IORESOURCE_MEM;
 	snprintf((char *)hpet_res->name, HPET_RESOURCE_NAME_SIZE, "HPET %u",