sparc: fix bad merge of sparc Kconfig

Fixes this sparc32 defconfig build error:

timekeeping.c:(.text+0x277c4): undefined reference to `arch_gettimeoffset'

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>