staging: wilc1000: host_interface.c : removes unused local variables

This patch removes unused local variables from host_interface.c.
The unused local variable, s32Error is used just to return zero, so this
patch calls "returns 0" instead of "return s32Error" after removing
s32Error.

Signed-off-by: Leo Kim <leo.kim@atmel.com>
Signed-off-by: Tony Cho <tony.cho@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>