sc16is7xx: put err_spi and err_i2c into correct #ifdef

err_spi is only called within SERIAL_SC16IS7XX_SPI
while err_i2c is called inside SERIAL_SC16IS7XX_I2C.
So we need to put err_spi and err_i2c into each #ifdef
accordingly.

This change fixes ("sc16is7xx: move label 'err_spi'
to correct section").

Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>