riscv: do not select MODULE_SECTIONS by default

Since commit aad15bc ("riscv: Change code model of module to
medany to improve data accessing"), kernel modules have not been built
with -fPIC, so they wouldn't have R_RISCV_GOT_HI20 or R_RISCV_CALL_PLT
relocations, and handling of those relocations is unnecessary.

If RELOCATABLE=y, kernel modules will be built with -fPIE, which would
reintroduce said relocations, so only select MODULE_SECTIONS when
RELOCATABLE.

Signed-off-by: Qingfang Deng <qingfang.deng@siflower.com.cn>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Link: https://lore.kernel.org/r/20240511015725.1162-1-dqfext@gmail.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

Author: LGA1150

arch/riscv/Kconfig

@@ -176,7 +176,6 @@ config RISCV
 	select LOCK_MM_AND_FIND_VMA
 	select MMU_GATHER_RCU_TABLE_FREE if SMP && MMU
 	select MODULES_USE_ELF_RELA if MODULES
-	select MODULE_SECTIONS if MODULES
 	select OF
 	select OF_EARLY_FLATTREE
 	select OF_IRQ
@@ -867,6 +866,7 @@ config PARAVIRT_TIME_ACCOUNTING
 config RELOCATABLE
 	bool "Build a relocatable kernel"
 	depends on MMU && 64BIT && !XIP_KERNEL
+	select MODULE_SECTIONS if MODULES
 	help
           This builds a kernel as a Position Independent Executable (PIE),
           which retains all relocation metadata required to relocate the