arm64: add early_ioremap support

arm64: add early_ioremap support

Add support for early IO or memory mappings which are needed before the
normal ioremap() is usable.  This also adds fixmap support for permanent
fixed mappings such as that used by the earlyprintk device register
region.

Signed-off-by: Mark Salter <[email protected]>
Acked-by: Catalin Marinas <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dave Young <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>