Searching in volume 0 is necessary for multiboot targets with only
one drive, like the M3K/Q1/ErosQ. Without this the search code will
never look at the redirect file on these targets.
The search bound is configured with a setting MULTIBOOT_MIN_VOLUME,
which defaults to 0, but is defined to 1 for Sansa players so they
keep their old behavior.
Change-Id: I6dc5cf98db4258731de2c68c3ab1182b4a4a655b
