boards: msp_exp432p401r_launchxl: Remove outdated links

This commit removes all links in the board documentation that are no
longer available.

The MSP432 series is now obsolete and TI seems to have intentionally
removed these links.

Signed-off-by: Stephanos Ioannidis <[email protected]>

Author: stephanosio

boards/arm/msp_exp432p401r_launchxl/doc/index.rst

@@ -26,7 +26,7 @@ Features:
 * Backchannel UART through USB to PC
 
 Details on the MSP-EXP432P401R LaunchXL development board can be found in the
-`MSP-EXP432P401R LaunchXL User's Guide`_.
+MSP-EXP432P401R LaunchXL User's Guide.
 
 Supported Features
 ==================
@@ -49,7 +49,7 @@ The MSP-EXP432P401R LaunchXL development board configuration supports the follow
 | UART      | on-chip    | serial port           |
 +-----------+------------+-----------------------+
 
-More details about the supported peripherals are available in `MSP432P4XX TRM`_
+More details about the supported peripherals are available in MSP432P4XX TRM
 Other hardware features are not currently supported by the Zephyr kernel.
 
 Building and Flashing
@@ -93,9 +93,9 @@ Debugging
 =========
 
 MSP-EXP432P401R LaunchXL board supports debugging primarily using `CCS IDE`_. More information
-on debugging using CCS can be found in `CCS Debug Handbook`_.
+on debugging using CCS can be found in CCS Debug Handbook.
 
-Launchpad also supports debugging using GDB. See section 3.3 of `GCC ARM Toolchain Guide`_.
+Launchpad also supports debugging using GDB. See section 3.3 of GCC ARM Toolchain Guide.
 
 References
 **********
@@ -109,20 +109,8 @@ TI MSP432P401R Product Page:
 TI MSP432 SDK:
    http://www.ti.com/tool/SIMPLELINK-MSP432-SDK
 
-.. _MSP-EXP432P401R LaunchXL User's Guide:
-   http://www.ti.com/lit/ug/slau597c/slau597c.pdf
-
-.. _MSP432P4XX TRM:
-   http://www.ti.com/lit/ug/slau356f/slau356f.pdf
-
 .. _UniFlash:
    http://processors.wiki.ti.com/index.php/UniFlash_v4_Quick_Guide#Command_Line_Interface
 
 .. _CCS IDE:
    http://www.ti.com/tool/ccstudio
-
-.. _CCS Debug Handbook:
-   http://processors.wiki.ti.com/index.php/Debug_Handbook_for_CCS#Cortex_M3.2FM4.2FTiva.2FMSP432
-
-.. _GCC ARM Toolchain Guide:
-   http://www.ti.com/lit/ug/slau688b/slau688b.pdf