drm/panfrost: fix -Wmissing-prototypes warnings

We get these warnings when build kernel W=1:
drivers/gpu/drm/panfrost/panfrost_perfcnt.c:35:6: warning: no previous prototype for ‘panfrost_perfcnt_clean_cache_done’ [-Wmissing-prototypes]
drivers/gpu/drm/panfrost/panfrost_perfcnt.c:40:6: warning: no previous prototype for ‘panfrost_perfcnt_sample_done’ [-Wmissing-prototypes]
drivers/gpu/drm/panfrost/panfrost_perfcnt.c:190:5: warning: no previous prototype for ‘panfrost_ioctl_perfcnt_enable’ [-Wmissing-prototypes]
drivers/gpu/drm/panfrost/panfrost_perfcnt.c:218:5: warning: no previous prototype for ‘panfrost_ioctl_perfcnt_dump’ [-Wmissing-prototypes]
drivers/gpu/drm/panfrost/panfrost_perfcnt.c:250:6: warning: no previous prototype for ‘panfrost_perfcnt_close’ [-Wmissing-prototypes]
drivers/gpu/drm/panfrost/panfrost_perfcnt.c:264:5: warning: no previous prototype for ‘panfrost_perfcnt_init’ [-Wmissing-prototypes]
drivers/gpu/drm/panfrost/panfrost_perfcnt.c:320:6: warning: no previous prototype for ‘panfrost_perfcnt_fini’ [-Wmissing-prototypes]
drivers/gpu/drm/panfrost/panfrost_mmu.c:227:6: warning: no previous prototype for ‘panfrost_mmu_flush_range’ [-Wmissing-prototypes]
drivers/gpu/drm/panfrost/panfrost_mmu.c:435:5: warning: no previous prototype for ‘panfrost_mmu_map_fault_addr’ [-Wmissing-prototypes]

For file panfrost_mmu.c, make functions static to fix this.
For file panfrost_perfcnt.c, include header file can fix this.

Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
Reviewed-by: Steven Price <steven.price@arm.com>
Cc: stable@vger.kernel.org
[robh: fixup function parameter alignment]
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1571967015-42854-1-git-send-email-wang.yi59@zte.com.cn

drivers/gpu/drm/panfrost/panfrost_mmu.c

@@ -224,9 +224,9 @@ static size_t get_pgsize(u64 addr, size_t size)
 	return SZ_2M;
 }
 
-void panfrost_mmu_flush_range(struct panfrost_device *pfdev,
-			      struct panfrost_mmu *mmu,
-			      u64 iova, size_t size)
+static void panfrost_mmu_flush_range(struct panfrost_device *pfdev,
+				     struct panfrost_mmu *mmu,
+				     u64 iova, size_t size)
 {
 	if (mmu->as < 0)
 		return;
@@ -432,7 +432,8 @@ addr_to_drm_mm_node(struct panfrost_device *pfdev, int as, u64 addr)
 
 #define NUM_FAULT_PAGES (SZ_2M / PAGE_SIZE)
 
-int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as, u64 addr)
+static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as,
+				       u64 addr)
 {
 	int ret, i;
 	struct panfrost_gem_object *bo;

drivers/gpu/drm/panfrost/panfrost_perfcnt.c

@@ -16,6 +16,7 @@
 #include "panfrost_issues.h"
 #include "panfrost_job.h"
 #include "panfrost_mmu.h"
+#include "panfrost_perfcnt.h"
 #include "panfrost_regs.h"
 
 #define COUNTERS_PER_BLOCK		64