[PATCH -next] module: fix build error when CONFIG_SMP is disabled

[Bixuan Cui <cuibixuan@huawei.com>]

Fix build error when disable CONFIG_SMP:
mm/pgtable-generic.o: In function `.L19':
pgtable-generic.c:(.text+0x42): undefined reference to `flush_pmd_tlb_range'
mm/pgtable-generic.o: In function `pmdp_huge_clear_flush':
pgtable-generic.c:(.text+0x6c): undefined reference to `flush_pmd_tlb_range'
mm/pgtable-generic.o: In function `pmdp_invalidate':
pgtable-generic.c:(.text+0x162): undefined reference to `flush_pmd_tlb_range'

Fixes: e88b333142e4 ("riscv: mm: add THP support on 64-bit")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Bixuan Cui <cuibixuan@huawei.com>
---
 arch/riscv/include/asm/tlbflush.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/riscv/include/asm/tlbflush.h b/arch/riscv/include/asm/tlbflush.h
index c84218ad7afc..9d5801f6e2c3 100644
--- a/arch/riscv/include/asm/tlbflush.h
+++ b/arch/riscv/include/asm/tlbflush.h
@@ -44,6 +44,12 @@ static inline void flush_tlb_range(struct vm_area_struct *vma,
 	local_flush_tlb_all();
 }
 
+static inline void flush_pmd_tlb_range(struct vm_area_struct *vma,
+		unsigned long start, unsigned long end)
+{
+	local_flush_tlb_all();
+}
+
 #define flush_tlb_mm(mm) flush_tlb_all()
 #endif /* !CONFIG_SMP || !CONFIG_MMU */
 
-- 
2.17.1