Fix about a dozen compile warnings

Summary:
It fixes the following compile warnings:
1. '0' flag ignored with precision and ‘%d’ gnu_printf format
2. enumeral and non-enumeral type in conditional expression
3. format ‘%d’ expects argument of type ‘int’, but argument 4 has type ...
4. enumeration value ‘...’ not handled in switch
5. cast from type ‘const uint64_t* {aka ...}’ to type ‘int64_t* {aka ...}’ casts away qualifiers
6. extra ‘;’
7. comparison between signed and unsigned integer expressions
8. variable ‘register_operand’ set but not used
9. control reaches end of non-void function

Reviewers: jingham, emaste, zturner, clayborg

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D24331

llvm-svn: 281191