Update Linux to v5.4.148

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz

Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c
index 3f15938..c54bd3c 100644
--- a/arch/riscv/mm/cacheflush.c
+++ b/arch/riscv/mm/cacheflush.c
@@ -14,6 +14,7 @@
 {
 	sbi_remote_fence_i(NULL);
 }
+EXPORT_SYMBOL(flush_icache_all);
 
 /*
  * Performs an icache flush for the given MM context.  RISC-V has no direct