x86: ifdtool: Drop microcode from the device tree when collating

x86: ifdtool: Drop microcode from the device tree when collating

When ifdtool collates the microcode into one place it effectively creates
a copy of the 'data' properties in the device tree microcode nodes. This
is wasteful since we now have two copies of the microcode in the ROM.

To avoid this, remove the microcode data from the device tree and shrink it
down. This means that there is only one copy and the overall ROM space used
by the microcode does not increase.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>