Documentation: isdn: correct spelling

Correct spelling problems for Documentation/isdn/ as reported
by codespell.

Signed-off-by: Randy Dunlap <[e-mail]>
Cc: Karsten Keil <[e-mail]>
Cc: Jonathan Corbet <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

Documentation/isdn/interface_capi.rst

···
 application up and down events.
 
 In addition, every registered CAPI controller has an associated traceflag
-parameter controlling how CAPI messages sent from and to tha controller are
+parameter controlling how CAPI messages sent from and to the controller are
 logged. The traceflag parameter is initialized with the value of the
 showcapimsgs parameter when the controller is registered, but can later be
 changed via the MANUFACTURER_REQ command KCAPI_CMD_TRACE.

Documentation/isdn/m_isdn.rst

···
 ============
 
 mISDN is a new modular ISDN driver, in the long term it should replace
-the old I4L driver architecture for passiv ISDN cards.
+the old I4L driver architecture for passive ISDN cards.
 It was designed to allow a broad range of applications and interfaces
 but only have the basic function in kernel, the interface to the user
 space is based on sockets with a own address family AF_ISDN.