riscv: Implement ARCH_HAS_CC_CAN_LINK

riscv: Implement ARCH_HAS_CC_CAN_LINK

The generic CC_CAN_LINK detection relies on -m32/-m64 compiler flags.
These are not supported by riscv compilers.

Use architecture-specific logic using -mabi instead.

Prefer the 'd' ABI variant when possible as todays toolchains are most
likely to provide a libc for that one.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Link: https://patch.msgid.link/20260316-cc-can-link-riscv-v4-1-64c072b456dd@linutronix.de
Signed-off-by: Paul Walmsley <pjw@kernel.org>