Declare __page_shift and __page_size with C linkage

__page_shift and __page_size are defined in asm/page.h with
C linkage - their implementation needs to use the same linkage.

The different linkage types cause a compiler error with clang.
Fixing them seems to be a good idea regardless of the compiler.

Change-Id: I35ed66a08989ced1db422eb03e4d154a5d6b5bda
Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>
Fix mismatch between declaration and forward declaration

KernelArgumentBlock is defined as a class in KernelArgumentBlock.h, but
forward declarations refer to it as a struct.

While this is essentially the same, the mismatch causes a compiler
warning in clang (and may cause warnings in future versions of gcc) in
code that is supposed to be compiled with -Werror.

Change-Id: I58c34563d6b9f78b47f40e4a92ee0c0aa3992ecd
Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>
Redo clang patch in a way that doesn't break gcc 4.8

Change-Id: I6b0ed3cf05b552c982f851d161c5bcb7f1cd5930
Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>