[PATCH v4 2/2] arm/gic_v3: address violations of MISRA C Rule 2.1

[Dmytro Prokopchuk1 <dmytro_prokopchuk1@xxxxxxxx>]

MISRA C Rule 2.1 states: "A project shall not contain unreachable code".
In certain build configuration the following 'gicv3_its_setup_collection()'
function is defined as inline and contains the macro 'BUG()'. This resulted
in violation due to the function became non-returning.

To ensure compliance with MISRA C Rule 2.1 remove inline function and its
'BUG()'-based unreachable code. Provide unconditional function declaration
for 'gicv3_its_setup_collection()'. Rely on the compiler's DCE to remove
unused function calls, and use the 'gicv3_its_host_has_its()' predicate,
which always returns false when 'CONFIG_HAS_ITS' is disabled, to statically
resolve conditional branches:
    if ( gicv3_its_host_has_its() )
    {
        ...
        ret = gicv3_its_setup_collection(smp_processor_id());
        if ( ret )
            return ret;
    }

Signed-off-by: Dmytro Prokopchuk <dmytro_prokopchuk1@xxxxxxxx>
---
 xen/arch/arm/include/asm/gic_v3_its.h | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/xen/arch/arm/include/asm/gic_v3_its.h 
b/xen/arch/arm/include/asm/gic_v3_its.h
index 0737e67aa6..fc5a84892c 100644
--- a/xen/arch/arm/include/asm/gic_v3_its.h
+++ b/xen/arch/arm/include/asm/gic_v3_its.h
@@ -131,6 +131,8 @@ struct host_its {
     unsigned int flags;
 };
 
+/* Map a collection for this host CPU to each host ITS. */
+int gicv3_its_setup_collection(unsigned int cpu);
 
 #ifdef CONFIG_HAS_ITS
 
@@ -160,9 +162,6 @@ int gicv3_its_init(void);
 void gicv3_set_redist_address(paddr_t address, unsigned int redist_id);
 uint64_t gicv3_get_redist_address(unsigned int cpu, bool use_pta);
 
-/* Map a collection for this host CPU to each host ITS. */
-int gicv3_its_setup_collection(unsigned int cpu);
-
 /* Initialize and destroy the per-domain parts of the virtual ITS support. */
 int vgic_v3_its_init_domain(struct domain *d);
 void vgic_v3_its_free_domain(struct domain *d);
@@ -256,12 +255,6 @@ static inline void gicv3_set_redist_address(paddr_t 
address,
 {
 }
 
-static inline int gicv3_its_setup_collection(unsigned int cpu)
-{
-    /* We should never get here without an ITS. */
-    BUG();
-}
-
 static inline int vgic_v3_its_init_domain(struct domain *d)
 {
     return 0;
-- 
2.43.0