rockchip: spl_common: fix TIMER_FMODE constant

rockchip: spl_common: fix TIMER_FMODE constant

The free running mode is 0 at bit offset 1. User mode is 1 at bit offset
1. Currently, free running mode is 1 at offset 0, which is already the
case thanks to TIME_EN.

So, this essentially does not change the actual value written to the
register as it is TIME_EN | TIMER_FMODE which currently is 0x1 | BIT(0)
= 0b1, and will become 0x1 | (0 << 1) = 0b1.

I checked PX30, RK3128, RK3188, RK3228, RK3288, RK3308, RK3328, RK3368
RK3506, RK3562 and RK3568 TRMs.

Signed-off-by: Quentin Schulz <quentin.schulz@cherry.de>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>