serial: lpc32xx_hs: remove redundant check and assignment of hsu_rate

serial: lpc32xx_hs: remove redundant check and assignment of hsu_rate

Variable hsu_rate is being checked for an upper limit and is assigned
a value that is never read. The if statement and assignment are
redundant and can be removed.

Cleans up clang scan build warning:
drivers/tty/serial/lpc32xx_hs.c:237:3: warning: Value stored
to 'hsu_rate' is never read [deadcode.DeadStores]

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20240215232944.2075789-1-colin.i.king@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>