video: fbdev: acornfb: remove free_unused_pages()

Patch series "mm: simplify free_highmem_page() and free_reserved_page()".

Let's simplify and unify free_highmem_page() and free_reserved_page().

This patch (of 2):

This function is never used and it is one of the last remaining user of
__free_reserved_page().  Let's just drop it.

Link: https://lkml.kernel.org/r/20210126182113.19892-1-david@redhat.com
Link: https://lkml.kernel.org/r/20210126182113.19892-2-david@redhat.com
Fixes: ffd29195

 ("drivers/video/acornfb.c: remove dead code")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>