arm64: sysreg: fix sparse warnings

Specify correct type for the constants to avoid
the following sparse complaints:

./arch/arm64/include/asm/sysreg.h:471:42: warning: constant 0xffffffffffffffff is so big it is unsigned long
./arch/arm64/include/asm/sysreg.h:512:42: warning: constant 0xffffffffffffffff is so big it is unsigned long

Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: Sergey Matyukevich <geomatsi@gmail.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>