kconfig: Replace some single-symbol 'if's with 'depends on'

I think people might be reading differences into 'if' and 'depends on'
that aren't there, like maybe 'if' being needed to "hide" a symbol,
while 'depends on' just adds a dependency.

There are no differences between 'if' and 'depends on'. 'if' is just a
shorthand for 'depends on'. They work the same when it comes to creating
implicit menus too.

The way symbols get "hidden" is through their dependencies not being
satisfied ('if'/'depends on' get copied up as a dependency on the
prompt).

Since 'if' and 'depends on' are the same, an 'if' with just a single
symbol in it can be replaced with a 'depends on'. IMO, it's best to
avoid 'if' there as a style choice too, because it confuses people into
thinking there's deep Kconfig magic going on that requires 'if'.

Going for 'depends on' can also remove some nested 'if's, which
generates nicer symbol information and docs, because nested 'if's really
are so simple/dumb that they just add the dependencies from both 'if's
to all symbols within.

Replace a bunch of single-symbol 'if's with 'depends on' to despam the
Kconfig files a bit and make it clearer how things work. Also do some
other minor related dependency refactoring.

The replacement isn't complete. Will fix up the rest later. Splitting it
a bit to make it more manageable.

(Everything above is true for choices, menus, and comments as well.)

Detected by tweaking the Kconfiglib parsing code. It's impossible to
detect after parsing, because 'if' turns into 'depends on'.

Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>

subsys/cpp/Kconfig

@@ -44,10 +44,9 @@ config STD_CPP2A
 
 endchoice
 
-if ! MINIMAL_LIBC
-
 config LIB_CPLUSPLUS
 	bool "Link with STD C++ library"
+	depends on !MINIMAL_LIBC
 	help
 	  Link with STD C++ Library.
 
@@ -65,6 +64,4 @@ config RTTI
 
 endif # LIB_CPLUSPLUS
 
-endif # ! MINIMAL_LIBC
-
 endif # CPLUSPLUS