staging: pi433: replace INVALID_PARAM macro with inline code

The following macro:
\#define INVALID_PARAM
	{ \
                dev_dbg(&spi->dev, "set: illegal input param"); \
                return -EINVAL; \
        }
affects control flow by having return statement. This is against
Linux Kernel Coding Style and should be avoided and therefore
this macro is replaced by inline code.

Additionally following 3 minor issues:

ERROR: code indent should use tabs where possible
ERROR: spaces required around that '!=' (ctx:VxV)
ERROR: space prohibited before that close parenthesis ')'

were fiexed inline.
Signed-off-by: Marcin Ciupak <marcin.s.ciupak@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>