ARM: use "depends on" for SoC configs instead of "if" after prompt

Many ARM sub-architectures use prompts followed by "if" conditional,
but it is wrong.

Please notice the difference between

    config ARCH_FOO
            bool "Foo SoCs" if ARCH_MULTI_V7

and

    config ARCH_FOO
            bool "Foo SoCs"
            depends on ARCH_MULTI_V7

These two are *not* equivalent!

In the former statement, it is not ARCH_FOO, but its prompt that
depends on ARCH_MULTI_V7.  So, it is completely valid that ARCH_FOO
is selected by another, but ARCH_MULTI_V7 is still disabled. As it is
not unmet dependency, Kconfig never warns.  This is probably not what
you want.

The former should be used only when you need to do so, and you really
understand what you are doing.  (In most cases, it should be wrong!)

For enabling/disabling sub-architectures, the latter is always correct.

As a good side effect, this commit fixes some entries over 80 columns
(mach-imx, mach-integrator, mach-mbevu).

[Arnd: I note that there is not really a bug here, according to
 the discussion that followed, but I can see value in being consistent
 and in making the lines shorter]

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Patrice Chotard <patrice.chotard@st.com>
Acked-by: Liviu Dudau <Liviu.Dudau@arm.com>
Acked-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Jun Nie <jun.nie@linaro.org>
Acked-by: Matthias Brugger <matthias.bgg@gmail.com>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Acked-by: Shawn Guo <shawnguo@kernel.org>
Acked-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Acked-by: Krzysztof Halasa <khc@piap.pl>
Acked-by: Maxime Coquelin <maxime.coquelin@st.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>