kconfig: Clean up header comments and make them consistent

Use this short header style in all Kconfig files:

    # <description>

    # <copyright>
    # <license>

    ...

Also change all <description>s from

    # Kconfig[.extension] - Foo-related options

to just

    # Foo-related options

It's clear enough that it's about Kconfig.

The <description> cleanup was done with this command, along with some
manual cleanup (big letter at the start, etc.)

    git ls-files '*Kconfig*' | \
        xargs sed -i -E '1 s/#\s*Kconfig[\w.-]*\s*-\s*/# /'

Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
diff --git a/modules/Kconfig.simplelink b/modules/Kconfig.simplelink
index 8fa3bba..4506a91 100644
--- a/modules/Kconfig.simplelink
+++ b/modules/Kconfig.simplelink
@@ -1,4 +1,4 @@
-# Kconfig - CC3220/CC32XX SDK HAL configuration
+# CC3220/CC32XX SDK HAL configuration
 
 config HAS_CC3220SDK
 	bool
@@ -19,13 +19,13 @@
 	help
 	  Build the SimpleLink host driver
 
-# Kconfig - MSP432 SDK HAL configuration
+# MSP432 SDK HAL configuration
 
 config HAS_MSP432P4XXSDK
 	bool
 	select HAS_CMSIS_CORE
 
-# Kconfig - CC13X2 / CC26X2 SDK HAL configuration
+# CC13X2 / CC26X2 SDK HAL configuration
 
 config HAS_CC13X2_CC26X2_SDK
 	bool