soc/qualcomm/common: Use bitwise OR for global_attributes

Ensure that existing flags in global_attributes are not overwritten
when enabling UART logging. Using a bitwise OR preserves any
previously set attributes.

BUG=b:457566143
TEST=Verify the QcLib global attributes.

With this CL -
```
[DEBUG]  Global Attributes[0x3]..Table Entries Count[8]
```

Change-Id: Iffceb06cb800ba4c9e5c07381745cbed1fb7d550
Signed-off-by: Kapil Porwal <kapilporwal@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/90509
Reviewed-by: Subrata Banik <subratabanik@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/qualcomm/common/qclib.c

@@ -213,7 +213,7 @@ static void qclib_prepare_and_run(void)
 
 	/* Enable QCLib serial output, if below condition is met */
 	if (CONFIG(CONSOLE_SERIAL) && qclib_debug_log_level())
-		qclib_cb_if_table.global_attributes =
+		qclib_cb_if_table.global_attributes |=
 			QCLIB_GA_ENABLE_UART_LOGGING;
 
 	dump_te_table();