dtc/powerpc: remove obsolete .gitignore entries

dtc was moved and .gitignores have been added to the new location. So, we can
delete the old, forgotten ones.

Signed-off-by: Wolfram Sang <[e-mail]>
Cc: Benjamin Herrenschmidt <[e-mail]>
Signed-off-by: Grant Likely <[e-mail]>

arch/powerpc/boot/.gitignore

···
 addnote
-dtc
 empty.c
 hack-coff
 infblock.c

arch/powerpc/boot/dtc-src/.gitignore

···
-dtc-lexer.lex.c
-dtc-parser.tab.c
-dtc-parser.tab.h