i2c: efm32: Omit superfluous error message in efm32_i2c_probe()

In the function efm32_i2c_probe(),when get irq failed,the function
platform_get_irq() logs an error message,so remove redundant message
here.

Signed-off-by: Shengju Zhang <zhangshengju@cmss.chinamobile.com>
Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>