ufs: ti-j721e: Correct error detection

ufs: ti-j721e: Correct error detection

In ti_j721e_ufs_probe there is a call to clk_get_rate but the code after
that attempts to detect an error from that call incorrectly uses
IS_ERR_VALUE.  Instead the test should just be for regular error codes.
The call returns an unsigned long so that needs to be cast to a signed type
first of all.

This issue was found by Smatch.

Signed-off-by: Andrew Goodbody <andrew.goodbody@linaro.org>
Reviewed-by: Anshul Dalal <anshuld@ti.com>
Link: https://patch.msgid.link/20251007-ufs_ti-v2-1-501f575b6947@linaro.org
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>