Revert "tty: n_gsm: avoid call of sleeping functions from atomic context"

stable inclusion
from stable-v5.10.158
commit b7f7a0402eb7332e1f81241368766044f40475ac
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7NTXH

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b7f7a0402eb7332e1f81241368766044f40475ac



--------------------------------

commit acdab4cb upstream.

This reverts commit 902e02ea.

The above commit is reverted as the usage of tx_mutex seems not to solve
the problem described in 902e02ea ("tty: n_gsm: avoid call of sleeping
functions from atomic context") and just moves the bug to another place.

Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Reviewed-by: Daniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20221008110221.13645-2-pchelkin@ispras.ru


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>