op_parameters: Use unsigned_literal for read/write

decoder_buffer_delay and encoder_buffer_delay are read / written using
'encoder_decoder_buffer_delay_length' bits.

And 'encoder_decoder_buffer_delay_length' is read from bitstream as a
5-bit value + 1. So, it has a range of 1 to 32.

So, as the max number of bits for reading/writing decoder_buffer_delay
and encoder_buffer_delay are 32, we should be using
aom_rb_read_unsigned_literal() ind aom_wb_write_unsigned_literal()
functions, which support max 'bits' value of 32.

BUG=oss-fuzz:9126

Change-Id: I3896259f79613f5b82bda431756086dc9fea773e

av1/common/timing.h

diff --git a/av1/common/timing.h b/av1/common/timing.h
index d31f4b7..2562951 100644
--- a/av1/common/timing.h
+++ b/av1/common/timing.h
@@ -35,8 +35,8 @@
   int decoder_model_param_present_flag;
   int64_t bitrate;
   int64_t buffer_size;
-  int decoder_buffer_delay;
-  int encoder_buffer_delay;
+  uint32_t decoder_buffer_delay;
+  uint32_t encoder_buffer_delay;
   int low_delay_mode_flag;
   int display_model_param_present_flag;
   int initial_display_delay;