lavfi/vf_xxx_vaapi: fix typo.

Signed-off-by: Jun Zhao <jun.zhao@intel.com>

libavfilter/vf_deinterlace_vaapi.c

@@ -33,7 +33,7 @@
 #define MAX_REFERENCES 8
 
 typedef struct DeintVAAPIContext {
-    VAAPIVPPContext vpp_ctx; // must be the first fileld
+    VAAPIVPPContext vpp_ctx; // must be the first field
 
     int                mode;
     int                field_rate;

libavfilter/vf_misc_vaapi.c

@@ -38,13 +38,13 @@
 #define SHARPNESS_DEFAULT      44
 
 typedef struct DenoiseVAAPIContext {
-    VAAPIVPPContext vpp_ctx; // must be the first fileld
+    VAAPIVPPContext vpp_ctx; // must be the first field
 
     int denoise;         // enable denoise algo.
 } DenoiseVAAPIContext;
 
 typedef struct SharpnessVAAPIContext {
-    VAAPIVPPContext vpp_ctx; // must be the first fileld
+    VAAPIVPPContext vpp_ctx; // must be the first field
 
     int sharpness;       // enable sharpness.
 } SharpnessVAAPIContext;

libavfilter/vf_procamp_vaapi.c

@@ -47,7 +47,7 @@
 #define EPSILON               0.00001F
 
 typedef struct ProcampVAAPIContext {
-    VAAPIVPPContext vpp_ctx; // must be the first fileld
+    VAAPIVPPContext vpp_ctx; // must be the first field
 
     float bright;
     float hue;

libavfilter/vf_scale_vaapi.c

@@ -31,7 +31,7 @@
 #include "vaapi_vpp.h"
 
 typedef struct ScaleVAAPIContext {
-    VAAPIVPPContext vpp_ctx; // must be the first fileld
+    VAAPIVPPContext vpp_ctx; // must be the first field
 
     char *output_format_string;