x86: linker script syntax nits

The linker scripts grew some use of weirdly wrong linker script syntax.
It happens to work, but it's not what the syntax is documented to be.
Clean it up to use the official syntax.
Signed-off-by: NRoland McGrath <roland@redhat.com>
CC: Ian Lance Taylor <iant@google.com>

arch/x86/kernel/acpi/realmode/wakeup.lds.S

@@ -56,6 +56,6 @@ SECTIONS
 	/DISCARD/ : {
 		*(.note*)
 	}
-
-	. = ASSERT(_end <= WAKEUP_SIZE, "Wakeup too big!");
 }
+
+ASSERT(_end <= WAKEUP_SIZE, "Wakeup too big!");

arch/x86/kernel/vmlinux.lds.S

@@ -305,8 +305,8 @@ SECTIONS
 
 
 #ifdef CONFIG_X86_32
-. = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE),
-	   "kernel image bigger than KERNEL_IMAGE_SIZE");
+ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE),
+       "kernel image bigger than KERNEL_IMAGE_SIZE");
 #else
 /*
  * Per-cpu symbols which need to be offset from __per_cpu_load
@@ -319,12 +319,12 @@ INIT_PER_CPU(irq_stack_union);
 /*
  * Build-time check on the image size:
  */
-. = ASSERT((_end - _text <= KERNEL_IMAGE_SIZE),
-	   "kernel image bigger than KERNEL_IMAGE_SIZE");
+ASSERT((_end - _text <= KERNEL_IMAGE_SIZE),
+       "kernel image bigger than KERNEL_IMAGE_SIZE");
 
 #ifdef CONFIG_SMP
-. = ASSERT((per_cpu__irq_stack_union == 0),
-           "irq_stack_union is not at start of per-cpu area");
+ASSERT((per_cpu__irq_stack_union == 0),
+       "irq_stack_union is not at start of per-cpu area");
 #endif
 
 #endif /* CONFIG_X86_32 */
@@ -332,7 +332,6 @@ INIT_PER_CPU(irq_stack_union);
 #ifdef CONFIG_KEXEC
 #include <asm/kexec.h>
 
-. = ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE,
-           "kexec control code size is too big");
+ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE,
+       "kexec control code size is too big");
 #endif
-