package/go: Fix powerpc64 config typo

Fix typo in config powerpc64 depends.  Go language only supports 64 bit powerpc.

Also add BR2_powerpc64le to depends list.

Signed-off-by: Geoff Levand <geoff@infradead.org>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>