rapidio/tsi721: remove redundant pci_clear_master

rapidio/tsi721: remove redundant pci_clear_master

Remove pci_clear_master to simplify the code, the bus-mastering is also
cleared in do_pci_disable_device, like this:

./drivers/pci/pci.c:2197
static void do_pci_disable_device(struct pci_dev *dev)
{
	u16 pci_command;

	pci_read_config_word(dev, PCI_COMMAND, &pci_command);
	if (pci_command & PCI_COMMAND_MASTER) {
		pci_command &= ~PCI_COMMAND_MASTER;
		pci_write_config_word(dev, PCI_COMMAND, pci_command);
	}

	pcibios_disable_device(dev);
}.
And dev->is_busmaster is set to 0 in pci_disable_device.

Link: https://lkml.kernel.org/r/20230323113711.10523-1-cai.huoqing@linux.dev
Signed-off-by: Cai Huoqing <cai.huoqing@linux.dev>
Cc: Alexandre Bounine <alex.bou9@gmail.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>