ARM: 8417/1: refactor bitops functions with BIT_MASK() and BIT_WORD()

Use BIT_MASK() and BIT_WORD() rather than hard-coding the size
of the "long" type.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>