ALSA: echoaudio: Fix improper return value in function load_asic

When the second call to load_asic_generic() fails in function
load_asic(), "false" is returned. The real value of "false" is 0, which
indicates success in the context. As a result, the execution status and
the return value may be inconsistent. This patch fixes the bug.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=188761
Signed-off-by: Pan Bian <bianpan2016@163.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>