The pseries HVC early debug options, CONFIG_PPC_EARLY_DEBUG_LPAR and
CONFIG_PPC_EARLY_DEBUG_LPAR_HVSI both require code that is part of the
hvc driver. If we turn them on but not CONFIG_HVC_CONSOLE then we get:

  arch/powerpc/kernel/built-in.o: In function `.udbg_early_init':
  arch/powerpc/kernel/built-in.o:(.debug_addr+0x9a00): undefined reference to `udbg_init_debug_lpar'

Similarly for HVSI. So make them both depend on CONFIG_HVC_CONSOLE.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>