staging: most: core: check value returned by match function

This patch adds a check for the pointer returned by the function
match_component. It is needed to prevent a NULL pointer dereference in
case the provided component name does not match any list entry.

Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>