imx: mx7: avoid some initialization if low level is skipped

We can have the case where u-boot is launched after some other low level
enabler, like for example when u-boot runs after arm-trusted-firmware
and/or optee. So, because of that we may need to jump the initialization of
some IP blocks even because we may no longer have the permission for that.

So, if the config option to skip low level init is set disable also timer,
board and csu initialization.

Signed-off-by: Rui Miguel Silva <rui.silva@linaro.org>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: u-boot@lists.denx.de
Reviewed-by: Peng Fan <peng.fan@nxp.com>

arch/arm/mach-imx/mx7/soc.c

@@ -164,6 +164,7 @@ u32 __weak get_board_rev(void)
 }
 #endif
 
+#ifndef CONFIG_SKIP_LOWLEVEL_INIT
 /* enable all periherial can be accessed in nosec mode */
 static void init_csu(void)
 {
@@ -285,6 +286,7 @@ int arch_cpu_init(void)
 
 	return 0;
 }
+#endif
 
 #ifdef CONFIG_ARCH_MISC_INIT
 int arch_misc_init(void)

arch/arm/mach-imx/syscounter.c

@@ -55,6 +55,7 @@ static inline unsigned long long us_to_tick(unsigned long long usec)
 	return usec;
 }
 
+#ifndef CONFIG_SKIP_LOWLEVEL_INIT
 int timer_init(void)
 {
 	struct sctr_regs *sctr = (struct sctr_regs *)SCTR_BASE_ADDR;
@@ -76,6 +77,7 @@ int timer_init(void)
 
 	return 0;
 }
+#endif
 
 unsigned long long get_ticks(void)
 {