sw64: kapi: use generic vga.h

Sunway inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I56OLG



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The old arch-specific vga.h takes no effect now, so use the
generic version. As a result, the arch-specific scr_memcpyw
interface and __is_ioaddr helper can be removed too.

Signed-off-by: He Sheng <hesheng@wxiat.com>

Signed-off-by: Gu Zitao <guzitao@wxiat.com>