arm: Update a stale comment in bootblock .S files

This just updates a comment which refers to "board_init_f". We use
bootblock main() in coreboot.

Change-Id: I4cb6b3c11f163b67fe48de495d13dce88710efc0
Reviewed-on: https://chromium-review.googlesource.com/172095
Reviewed-by: Gabe Black <gabeblack@chromium.org>
Commit-Queue: David Hendricks <dhendrix@chromium.org>
Tested-by: David Hendricks <dhendrix@chromium.org>
(cherry picked from commit 65139f29682cedca8dfb58b3dfe67eab64299064)
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6791
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Tested-by: build bot (Jenkins)

src/arch/arm/armv4/bootblock.S

@@ -65,7 +65,7 @@ init_stack_loop:
 	cmp	r0, r1
 	bne	init_stack_loop
 
-/* Set stackpointer in internal RAM to call board_init_f */
+/* Set stackpointer in internal RAM to call bootblock main() */
 call_bootblock:
 	ldr	sp, .Stack /* Set up stack pointer */
 	ldr	r0,=0x00000000

src/arch/arm/armv7/bootblock.S

@@ -66,7 +66,7 @@ init_stack_loop:
 	cmp	r0, r1
 	bne	init_stack_loop
 
-/* Set stackpointer in internal RAM to call board_init_f */
+/* Set stackpointer in internal RAM to call bootblock main() */
 call_bootblock:
 	ldr	sp, .Stack /* Set up stack pointer */
 	ldr	r0,=0x00000000

src/soc/nvidia/tegra124/bootblock_asm.S

@@ -65,7 +65,7 @@ init_stack_loop:
 	cmp	r0, r1
 	bne	init_stack_loop
 
-/* Set stackpointer in internal RAM to call board_init_f */
+/* Set stackpointer in internal RAM to call bootblock main() */
 call_bootblock:
 	ldr	sp, .Stack /* Set up stack pointer */
 	ldr	r0,=0x00000000