powerpc/cputable: Fix typo on P7+ cputable entry

Fix a typo in setting COMMON_USER2_POWER7 bits to .cpu_user_features2
cpu specs table.

Signed-off-by: Will Schmidt <will_schmidt@vnet.ibm.com>
Acked-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>