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/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index 8fd4f82..7fd1c18 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -316,6 +316,8 @@
 	}
 }
 
+extern void rcu_init_geometry(void);
+
 /* Returns a pointer to the first leaf rcu_node structure. */
 #define rcu_first_leaf_node() (rcu_state.level[rcu_num_lvls - 1])