serial: 8250: Remove serial_rs485 sanitization from em485

stable inclusion
from stable-v5.10.156
commit 85cdbf04b435d40db127869afb6611f13df9a02c
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7MCG1

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=85cdbf04b435d40db127869afb6611f13df9a02c



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[ Upstream commit 84f2faa7 ]

Serial core handles serial_rs485 sanitization.

When em485 init fails, there are two possible paths of entry:

  1) uart_rs485_config (init path) that fully clears port->rs485 on
     error.

  2) ioctl path with a pre-existing, valid port->rs485 unto which the
     kernel falls back on error and port->rs485 should therefore be
     kept untouched. The temporary rs485 struct is not returned to
     userspace in case of error so its flag don't matter.

...Thus SER_RS485_ENABLED clearing on error can/should be dropped.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-37-ilpo.jarvinen@linux.intel.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 93810191 ("serial: 8250: omap: Fix missing PM runtime calls for omap8250_set_mctrl()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>