arch/riscv: Use SPEED_OPTIMIZATIONS for GCC 14.3

GCC 14.3 has some compilation errors when using size optimizations, force
the use of -O2 on risc-v.

Signed-off-by: Keith Packard <keithp@keithp.com>

Author: keith-packard

Kconfig.zephyr

@@ -491,6 +491,8 @@ choice COMPILER_OPTIMIZATIONS
 	prompt "Optimization level"
 	default NO_OPTIMIZATIONS    if COVERAGE
 	default DEBUG_OPTIMIZATIONS if DEBUG
+	# gcc 14.3 -Os is broken on riscv. This setting should be in the SDK, it's here for testing
+	default SPEED_OPTIMIZATIONS if "$(TOOLCHAIN_VARIANT_COMPILER)" = "gnu" && RISCV
 	default SIZE_OPTIMIZATIONS_AGGRESSIVE if "$(TOOLCHAIN_VARIANT_COMPILER)" = "llvm"
 	default SIZE_OPTIMIZATIONS
 	help