bus: ti-sysc: Use fsleep() instead of usleep_range() in sysc_reset()

The am335x-evm started producing boot errors because of subtle timing
changes:

Unhandled fault: external abort on non-linefetch (0x1008) at 0xf03c1010
...
sysc_reset from sysc_probe+0xf60/0x1514
sysc_probe from platform_probe+0x5c/0xbc
...

The fix consists in using the appropriate sleep function in sysc reset.
For flexible sleeping, fsleep is recommended. Here, sysc delay parameter
can take any value in [0 - 255] us range. As a result, fsleep() should
be used, calling udelay() for a sysc delay lower than 10 us.

Signed-off-by: Julien Panis <jpanis@baylibre.com>
Fixes: e709ed70

 ("bus: ti-sysc: Fix missing reset delay handling")
Message-ID: <20230821-fix-ti-sysc-reset-v1-1-5a0a5d8fae55@baylibre.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>