spmi: get rid of a warning when built with W=1

spmi: get rid of a warning when built with W=1

The SPMI core complaing with this warning when built with W=1:

	drivers/spmi/spmi.c: In function ‘spmi_controller_remove’:
	drivers/spmi/spmi.c:548:6: warning: variable ‘dummy’ set but not used [-Wunused-but-set-variable]
	  548 |  int dummy;
	      |      ^~~~~

As the dummy var isn't needed, remove it.

Link: https://lore.kernel.org/r/aacfd03835b7d1b3b6c21665b44000fe7242e535.1601360391.git.mchehab+huawei@kernel.org
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20201210023344.2838141-2-sboyd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>