x86: extend e820 ealy_res support 32bit - fix #2

remove extra -1 in reseve_early calling
    panic if can not find space for new RAMDISK

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>