rockchip: Don't clear the reset status reg

reset reason can be used several stages of U-Boot bootloader
like SPL, U-Boot proper based on the requirements.

Clearing the status register end of get_reset_cause will end
up showing the wrong reset cause when it read the second time.
For example, if board resets, SPL reads the reset status as
RST whereas U-Boot proper reads the status as POR.

However, based on the latest testing clearing reset status
won't be required for determine the last reset cause or
following resets.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>

arch/arm/include/asm/arch-rockchip/cru.h

@@ -26,7 +26,6 @@ enum {
 	SND_GLB_TSADC_RST_ST	= BIT(3),
 	FST_GLB_WDT_RST_ST	= BIT(4),
 	SND_GLB_WDT_RST_ST	= BIT(5),
-	GLB_RST_ST_MASK		= GENMASK(5, 0),
 };
 
 #define MHz		1000000

arch/arm/mach-rockchip/cpu-info.c

@@ -47,12 +47,6 @@ static char *get_reset_cause(void)
 	 */
 	env_set("reset_reason", cause);
 
-	/*
-	 * Clear glb_rst_st, so we can determine the last reset cause
-	 * for following resets.
-	 */
-	rk_clrreg(&cru->glb_rst_st, GLB_RST_ST_MASK);
-
 	return cause;
 }