Revert "arm pl011 serial: support multi-irq request"

This reverts commit b0819465

 which
results in amba_device-specific code being called from
sbsa_uart_startup() and sbsa_uart_shutdown().

Signed-off-by: Qian Cai <quic_qiancai@quicinc.com>
Link: https://lore.kernel.org/r/20210813163135.205-1-quic_qiancai@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>