arm, xtensa: simplify initialization of high memory pages

arm, xtensa: simplify initialization of high memory pages

free_highpages() in both arm and xtensa essentially open-code
for_each_free_mem_range() loop to detect high memory pages that were not
reserved and that should be initialized and passed to the buddy allocator.

Replace open-coded implementation of for_each_free_mem_range() with usage
of memblock API to simplify the code.

Signed-off-by: Mike Rapoport <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Tested-by: Max Filippov <[email protected]>	[xtensa]
Reviewed-by: Max Filippov <[email protected]>	[xtensa]
Cc: Andy Lutomirski <[email protected]>
Cc: Baoquan He <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Daniel Axtens <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Emil Renner Berthing <[email protected]>
Cc: Hari Bathini <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jonathan Cameron <[email protected]>
Cc: Marek Szyprowski <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Michal Simek <[email protected]>
Cc: Miguel Ojeda <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Russell King <[email protected]>
Cc: Stafford Horne <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yoshinori Sato <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>