riscv: enable DEBUG_FORCE_FUNCTION_ALIGN_64B

Allow to force all function address 64B aligned as it is possible for
other architectures. This may be useful when verify if performance
bump is caused by function alignment changes.

Before commit 1bf18da6 ("lib/Kconfig.debug: add ARCH dependency
for FUNCTION_ALIGN option"), riscv supports enabling the
DEBUG_FORCE_FUNCTION_ALIGN_64B option, but after that commit, each
arch needs to claim the support explicitly.
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230727160356.3874-1-jszhang@kernel.orgSigned-off-by: Palmer Dabbelt <palmer@rivosinc.com>

lib/Kconfig.debug

@@ -502,7 +502,7 @@ config SECTION_MISMATCH_WARN_ONLY
 
 config DEBUG_FORCE_FUNCTION_ALIGN_64B
 	bool "Force all function address 64B aligned"
-	depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || S390)
+	depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || RISCV || S390)
 	select FUNCTION_ALIGNMENT_64B
 	help
 	  There are cases that a commit from one domain changes the function