staging: pi433: rf69.c style fix - spaces before/after

his patch fixes the following checkpatch.pl errors:

ERROR: space prohibited after that open parenthesis '('
ERROR: space prohibited before that ',' (ctx:WxV)
ERROR: space prohibited before that close parenthesis ')'
ERROR: space required after that ',' (ctx:VxV)
ERROR: space required before the open parenthesis '('

in rf69.c file as requested by TODO file.

Additionally some style warnings remain valid here and could be fixed by
another patch.
Signed-off-by: Marcin Ciupak <marcin.s.ciupak@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>