riscv: Respect dependencies of ARCH_HAS_ELF_CORE_EFLAGS

This kconfig symbol has dependencies and is only selectable if those
dependencies are also enabled.

Respect the dependencies.

Fixes the following warning when configuring an 'allnoconfig':

WARNING: unmet direct dependencies detected for ARCH_HAS_ELF_CORE_EFLAGS
  Depends on [n]: BINFMT_ELF [=n] && ELF_CORE [=y]
  Selected by [y]:
  - RISCV [=y]

Fixes: 8c94db0a ("binfmt_elf: preserve original ELF e_flags for core dumps")
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Link: https://lore.kernel.org/r/20251009-riscv-elf-core-eflags-v1-1-e9b45ab6b36d@linutronix.de


Signed-off-by: Paul Walmsley <pjw@kernel.org>