clocksource/drivers/timer-imx-tpm: Specify clock name for timer-of

i.MX TPM needs "ipg" clock for register access and "per" clock for
timer function, the driver gets "ipg" clock by searching the clock
name, but timer-of initialization will get first clock in device
tree TPM node since no clock name specified in of_clk, that means
the "per" clock MUST be the first clock entry in device tree TPM
node, this patch specifies clock name for of_clk to avoid this
restriction, it makes TPM driver work properly with different sequence
of clock entries in device tree TPM node.

Signed-off-by: Anson Huang <[e-mail]>
Signed-off-by: Daniel Lezcano <[e-mail]>

drivers/clocksource/timer-imx-tpm.c

···
 		.handler		= tpm_timer_interrupt,
 		.flags			= IRQF_TIMER | IRQF_IRQPOLL,
 	},
+	.of_clk = {
+		.name = "per",
+	},
 };
 
 static int __init tpm_clocksource_init(void)