RISC-V: lib: Add pi aliases for string functions

memset, strcmp, and strncmp are all used in the __pi_ section,
add SYM_FUNC_ALIAS for them.

When KASAN is enabled in <asm/string.h> __pi___memset is also needed.
Suggested-by: Charlie Jenkins <charlie@rivosinc.com>
Signed-off-by: Jesse Taube <jesse@rivosinc.com>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20240709173937.510084-3-jesse@rivosinc.comSigned-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/lib/memset.S

@@ -111,3 +111,5 @@ SYM_FUNC_START(__memset)
 	ret
 SYM_FUNC_END(__memset)
 SYM_FUNC_ALIAS_WEAK(memset, __memset)
+SYM_FUNC_ALIAS(__pi_memset, __memset)
+SYM_FUNC_ALIAS(__pi___memset, __memset)

arch/riscv/lib/strcmp.S

@@ -120,3 +120,4 @@ strcmp_zbb:
 .option pop
 #endif
 SYM_FUNC_END(strcmp)
+SYM_FUNC_ALIAS(__pi_strcmp, strcmp)

arch/riscv/lib/strncmp.S

@@ -136,3 +136,4 @@ strncmp_zbb:
 .option pop
 #endif
 SYM_FUNC_END(strncmp)
+SYM_FUNC_ALIAS(__pi_strncmp, strncmp)