refactor: make api functions static

Make api_switch_to_primary and api_ffa_msg_recv_block_interrupted static
in api.c.

Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
Change-Id: Icddff674314821f2bdb59c36762b1ea1159eb4d9
diff --git a/src/api.c b/src/api.c
index deb2249..6bb709f 100644
--- a/src/api.c
+++ b/src/api.c
@@ -128,9 +128,9 @@
  * This triggers the scheduling logic to run. Run in the context of secondary VM
  * to cause FFA_RUN to return and the primary VM to regain control of the CPU.
  */
-struct vcpu *api_switch_to_primary(struct vcpu *current,
-				   struct ffa_value primary_ret,
-				   enum vcpu_state secondary_state)
+static struct vcpu *api_switch_to_primary(struct vcpu *current,
+					  struct ffa_value primary_ret,
+					  enum vcpu_state secondary_state)
 {
 	/*
 	 * If the secondary is blocked but has a timer running, sleep until the
@@ -1593,7 +1593,7 @@
  * Checks whether the vCPU's attempt to block for a message has already been
  * interrupted or whether it is allowed to block.
  */
-bool api_ffa_msg_recv_block_interrupted(struct vcpu *current)
+static bool api_ffa_msg_recv_block_interrupted(struct vcpu *current)
 {
 	struct vcpu_locked current_locked;
 	bool interrupted;