arm64: pass endianness info to sparse

arm64: pass endianness info to sparse

ARM64 depends on the macro __AARCH64EB__ being defined or not
to correctly select or define endian-specific macros, structures
or pieces of code.

This macro is predefined by the compiler but sparse knows nothing
about it and thus may pre-process files differently from what
gcc would.

Fix this by passing '-D__AARCH64EL__' or '-D__AARCH64EB__' to
sparse depending of the endianness of the kernel, like defined
by GCC.

Note: In most case it won't change anything since most arm64 use
      little-endian (but an allyesconfig would use big-endian!).

CC: Catalin Marinas <[email protected]>
CC: Will Deacon <[email protected]>
CC: [email protected]
Signed-off-by: Luc Van Oostenryck <[email protected]>
Signed-off-by: Will Deacon <[email protected]>