linux-yocto: Remove debug-kernel.scc for riscv32 kernels

linux-yocto: Remove debug-kernel.scc for riscv32 kernels

modpost fails to process the debug location lists for riscv32

| ERROR: modpost: vmlinux: local symbol '__asm_copy_to_user' was exported
| ERROR: modpost: vmlinux: local symbol '__asm_copy_from_user' was exported
| ERROR: modpost: vmlinux: local symbol '__clear_user' was exported
| ERROR: modpost: vmlinux: local symbol 'xor_regs_2_' was exported
| ERROR: modpost: vmlinux: local symbol 'xor_regs_3_' was exported
| ERROR: modpost: vmlinux: local symbol 'xor_regs_4_' was exported
| ERROR: modpost: vmlinux: local symbol 'xor_regs_5_' was exported
| WARNING: modpost: vmlinux: section mismatch in reference: 0x1560 (section: __ex_table) -> .LASF464 (section: .debug_str)
| ERROR: modpost: __ex_table+0x1560 references non-executable section '.debug_str'

poky adds features/debug/debug-kernel.scc via distro policy and hence
the builds are failing for qemuriscv32 on AB. While this should be
fixed in kernel build system or tools, this makes us proceed until
then

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Cc: Bruce Ashfield <bruce.ashfield@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>