iPod Classic: enable IRAM1 in bootloader

7442742 ("iPod Classic: disable IRAM1") was causing subsequent ipod6g
bootloader builds to result in a completely black screen upon
installation, with recovery only possible with a reflash through DFU
mode.

IRAM1 is re-enabled for bootloader only.

Change-Id: I92d489c91f81cad55d66a8647c1e61a45f468770
1 file changed