clang-tidy: simplify bools

[neheb]

Found with readability-simplify-boolean-expr

Signed-off-by: Rosen Penev [email protected]

[codecov]

Codecov Report

Merging #1702 (4c238b3) into main (23dbf4f) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main    #1702   +/-   ##
=======================================
  Coverage   66.90%   66.90%           
=======================================
  Files         151      151           
  Lines       20764    20765    +1     
=======================================
+ Hits        13892    13893    +1     
  Misses       6872     6872           

Impacted Files	Coverage Δ
include/exiv2/image.hpp	100.00% <100.00%> (ø)
include/exiv2/types.hpp	90.90% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 23dbf4f...4c238b3. Read the comment docs.