gemini,layerscape,oxnas: don't disable option CONFIG_BPF_SYSCALL
Respect the generic kernel config setting, which is "enabled" tree-wide, as
previously done for sunxi.
Ref: 247ef4d98bab ("sunxi: enable CONFIG_BPF_SYSCALL and CONFIG_EMBEDDED")
Signed-off-by: Tony Ambardar <[email protected]>