Fix GCC build issue with Fedora (linux)

[Mystro256]

Building dolphin with Fedora 26 (in development) seems to cause the following error:

/builddir/build/BUILD/dolphin-5.0/Source/Core/VideoBackends/OGL/RasterFont.cpp:18:18: error: expected unqualified-id before numeric constant
 static const int CHAR_WIDTH = 8;

I assume this is because CHAR_WIDTH already exists as a "#define" somewhere.
Making it lowercase fixes the issue. I also changed the rest of the const's to lowercase for consistency.

EDIT: I've reworked it so CHAR_ is replaced by CHARACTER_ so style can be preserved. see below.

[JosJuice]

Our convention for Dolphin is to use uppercase for constants even if they aren't defines. Could you change the names to something else? Maybe CHARACTER instead of CHAR?

[BhaaLseN]

And I believe those can be made constexpr too?

[Mystro256]

@JosJuice Sounds good, I'll rework it to use "CHARACTER"

@BhaaLseN What version of C++ are you targeting? 11? Unfortunately work mostly with C++03 and before, so I'm a little unfamiliar with the new stuff added in 11.

[Mystro256]

Done, see new commit

[JosJuice]

The lint bot (running clang-format) is failing, so you'll need to format the lines the way it shows. (The max length for a line is 100 characters.)

[Mystro256]

Gotcha, I've made the style fixes and squashed the commits

[Parlane]

Thanks @Mystro256

[HarleyGaniere]

Thank you @Mystro256, as both a Fedora and Dolphin user this means a lot.

[Mystro256]

No problem, I maintain the official fedora dolphin package for a reason:
https://admin.fedoraproject.org/pkgdb/package/rpms/dolphin-emu/