arm: fix return value of parse_cpu_capacity

parse_cpu_capacity() has to return 0 on failure, but it currently returns
1 instead if raw_capacity kcalloc failed.

Fix it (by directly returning 0).

Reported-by: Morten Rasmussen <morten.rasmussen@arm.com>
Fixes: 06073ee2 ('ARM: 8621/3: parse cpu capacity-dmips-mhz from DT')
Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Vincent Guittot <vincent.guittot@linaor.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>