MAINTAINERS: Drop entry for PCA9541 bus master selector

I no longer have access to PCA9541 hardware, and I am no longer involved
in related development. Listing me as PCA9541 maintainer does not make
sense anymore. Remove PCA9541 from MAINTAINERS to let its support default
to the generic I2C multiplexer entry.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>