Ensure CTB size > 16 for clips with tiles and width/height >= 4096

For clips with tiles and dimensions >= 4096,
CTB size of 16 can result in tile position > 255.
This is not supported by the decoder

Bug: 37930177
Test: ran poc w/o crashing
Change-Id: I2f223a124c4ea9bfd98343343fd010d80a5dd8bd
(cherry picked from commit 248e72c7a8c7c382ff4397868a6c7453a6453141)

WORD32 ihevcd_extend_sign_bit(WORD32 value, WORD32 num_bits)
{
    WORD32 ret_value = value;
 if(value >> (num_bits - 1))
 {
        ret_value |= (0xFFFFFFFF << num_bits);
 }
 return ret_value;
}

WORD32 ihevcd_extend_sign_bit(WORD32 value, WORD32 num_bits)
{
    WORD32 ret_value = value;
 if(value >> (num_bits - 1))
 {
        ret_value |= (0xFFFFFFFF << num_bits);
 }
 return ret_value;
}
