ASoC: codecs: wcd9335: Remove potential undefined behavior in wcd9335_slimbus_irq()

If 'port_id' is negative, the shift counts in wcd9335_slimbus_irq() also
become negative, resulting in undefined behavior due to shift out of
bounds.

That appears to be not possible, but with UBSAN enabled, Clang's range
analysis isn't always able to determine that and generates undefined
behavior.

As a result the code generation isn't optimal, and undefined behavior
should be avoided regardless. Improve code generation and remove the
undefined behavior by converting the signed variables to unsigned.

Fixes the following warning:

sound/soc/codecs/wcd9335.o: warning: objtool: wcd9335_slimbus_irq() falls through to next function __cfi_wcd9335_set_channel_map()

This is very similar to a previous fix to wcd934x with commit
060aed9c0093 ("objtool, ASoC: codecs: wcd934x: Remove potential
undefined behavior in wcd934x_slim_irq_handler()").

Cc: Srinivas Kandagatla <srini@kernel.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Reported-by: Arnd Bergmann <arnd@arndb.de>
Closes: https://lore.kernel.org/a426d669-58bb-4be1-9eaa-6f3d83109e2d@app.fastmail.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/08dbb63519ef31a5457e07673b7b256fecb5989b.1773071992.git.jpoimboe@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>