mips32: pracc: Fix UPPER/LOWER macros

mips32: pracc: Fix UPPER/LOWER macros

These macros are missing parenthesis around the argument, which can
lead to side effects, add them. Replace the argument name to avoid
conflict with uint32_t data type, since the macro can be applied to
other data types as well.

Change-Id: I32d2ffec6c062795d7c8bb23d1dfa3378bfc3a58
Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Reviewed-on: http://openocd.zylin.com/4994
Tested-by: jenkins
Reviewed-by: Freddie Chopin <freddie.chopin@gmail.com>