git: Remove .gitignore

We discourage the use of per-repo .gitignore and encourage people to use
personal .gitignore to tell Git to ignore specific files. There also
isn't much point to have a per-repo .gitignore in the first place as we
do not build artifacts inside the repositories but rather inside
dedicated build directories.

.gitignore

diff --git a/.gitignore b/.gitignore
deleted file mode 100644
index bbf313b..0000000
--- a/.gitignore
+++ /dev/null
@@ -1,32 +0,0 @@
-# Object files
-*.o
-*.ko
-*.obj
-*.elf
-
-# Precompiled Headers
-*.gch
-*.pch
-
-# Libraries
-*.lib
-*.a
-*.la
-*.lo
-
-# Shared objects (inc. Windows DLLs)
-*.dll
-*.so
-*.so.*
-*.dylib
-
-# Executables
-*.exe
-*.out
-*.app
-*.i*86
-*.x86_64
-*.hex
-
-# Debug files
-*.dSYM/