libbb: split decode_base64 off read_base64

function                                             old     new   delta
decode_base64                                          -     182    +182
read_base64                                          378     255    -123
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(add/remove: 1/0 grow/shrink: 0/1 up/down: 182/-123)           Total: 59 bytes

Signed-off-by: Leonid Lisovskiy <lly.dev@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
3 files changed