sparc64: only select COMPAT_BINFMT_ELF if BINFMT_ELF is set

sparc64: only select COMPAT_BINFMT_ELF if BINFMT_ELF is set

Currently COMPAT on SPARC64 selects COMPAT_BINFMT_ELF unconditionally,
even when BINFMT_ELF is not enabled. This causes a kconfig warning.

Instead, just select COMPAT_BINFMT_ELF if BINFMT_ELF is enabled.
This builds cleanly with no kconfig warnings.

WARNING: unmet direct dependencies detected for COMPAT_BINFMT_ELF
  Depends on [n]: COMPAT [=y] && BINFMT_ELF [=n]
  Selected by [y]:
  - COMPAT [=y] && SPARC64 [=y]

Fixes: 26b4c912185a ("sparc,sparc64: unify Kconfig files")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>