drm/amdgpu/sdma5: fix number of sdma5 trap irq types for navi1x

v2: set num_types based on num_instances

navi1x has 2 sdma engines but commit
"e7b58d03b678 drm/amdgpu: reorganize sdma v4 code to support more instances"
changes the max number of sdma irq types (AMDGPU_SDMA_IRQ_LAST) from 2 to 8
which causes amdgpu_irq_gpu_reset_resume_helper() to recover irq of sdma
engines with following logic:

(enable irq for sdma0) * 1 time
(enable irq for sdma1) * 1 time
(disable irq for sdma1) * 6 times

as a result, after gpu reset, interrupt for sdma1 is lost.
Signed-off-by: Xiaojie Yuan <xiaojie.yuan@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c

@@ -1628,7 +1628,8 @@ static const struct amdgpu_irq_src_funcs sdma_v5_0_illegal_inst_irq_funcs = {
 
 static void sdma_v5_0_set_irq_funcs(struct amdgpu_device *adev)
 {
-	adev->sdma.trap_irq.num_types = AMDGPU_SDMA_IRQ_LAST;
+	adev->sdma.trap_irq.num_types = AMDGPU_SDMA_IRQ_INSTANCE0 +
+					adev->sdma.num_instances;
 	adev->sdma.trap_irq.funcs = &sdma_v5_0_trap_irq_funcs;
 	adev->sdma.illegal_inst_irq.funcs = &sdma_v5_0_illegal_inst_irq_funcs;
 }