[POWERPC] QE: Make qe_get_firmware_info reentrant

The function was returning NULL the second time it was
called if the firmware was uploaded from the boot loader
or the first time it was called if the firmware was
uploaded from the kernel.

Signed-off-by: Ionut Nicu <ionut.nicu@freescale.com>
Acked-By: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>