staging: rtl8712: remove redundant zero assignment to val32

Variable val32 is being assigned a zero value that is never read
since val32 is being updated immediately afterwards.  Remove this
redundant assignment, cleans up clang warning:

drivers/staging/rtl8712/hal_init.c:339:2: warning: Value stored
to 'val32' is never read

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>