hv: create 8-bit sum function

Move 8-bit sum code to a separate new function calculate_sum8() in
util.h and replace the old code with a call to calculate_sum8()

Minor code cleanup in found_rsdp() to make it more readable. Both break and
continue statements are used in a single for loop, changed to only use break
statement to make the logic simpler.

Fixed some coding style issues reported by checkpatch.pl for file
hypervisor/boot/acpi_base.c

Tracked-On: #3601
Signed-off-by: dongshen <dongsheng.x.zhang@intel.com>
Reviewed-by: Eddie Dong <eddie.dong@intel.com>

hypervisor/include/lib/util.h

@@ -31,4 +31,19 @@ static inline bool mem_aligned_check(uint64_t value, uint64_t req_align)
 	return ((value & (req_align - 1UL)) == 0UL);
 }
 
+/**
+ * @pre buf != NULL
+ */
+static inline uint8_t calculate_sum8(const void *buf, uint32_t length)
+{
+	uint32_t i;
+	uint8_t sum = 0U;
+
+	for (i = 0U; i < length; i++) {
+		sum += *((const uint8_t *)buf + i);
+	}
+
+	return sum;
+}
+
 #endif /* UTIL_H */